front axle & steering

CAPACITY TABLE OF CONTENTS

SECTION PAGE

1 GENERAL INFORMATIONSpecifications . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . .1-1Nomenclature . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . .1-3Fasteners . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . .1-4Torque Chart . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . .1-8Engine and Transmission Identification . . . . . . . . . . . . . . . . . . . . . . . . .1-10

2 PREVENTIVE MAINTENANCEPre-Operational Safety Inspection . . . . . . . . . . . . . . . . . . . . . . . . . . . . . .2-1Suggested Preventive Maintenance . . . . . . . . . . . . . . . . . . . . . . . . . . . . .2-2Daily . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . .2-2Weekly or 50 Hours of Operation . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . .2-2200 Hours of Operation . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . .2-2Quarterly or 500 Hours of Operation . . . . . . . . . . . . . . . . . . . . . . . . . . . .2-22 Years or 2000 Hours of Operation . . . . . . . . . . . . . . . . . . . . . . . . . . . . .2-23000 Hours of Operation . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . .2-2Engine Valve Adjustment . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . .2-23 Years or 6000 Hours of Operation . . . . . . . . . . . . . . . . . . . . . . . . . . . . .2-2Daily Maintenance Procedures . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . .2-3Maintenance Procedures - 250 Hours or 3 Months . . . . . . . . . . . . . . . . .2-5Maintenance Procedures 500 Hours of Operation . . . . . . . . . . . . . . . . . .2-6Maintenance Procedures 5000 Hours or 1 Year . . . . . . . . . . . . . . . . . .2-12Maintenance Procedures 2000 Hours or 2 Years . . . . . . . . . . . . . . . . . .2-16Recommended Lubrication and Capacities . . . . . . . . . . . . . . . . . . . . . .2-20Cooling System Recommendations . . . . . . . . . . . . . . . . . . . . . . . . . . . .2-20Tire Pressure Maximum Recommendations . . . . . . . . . . . . . . . . . . . . . .2-20Fuel Requirements . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . .2-20Lubrication Chart . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . .2-21

3 ELECTRICAL SYSTEMTerminal Objective and Enabling Objectives . . . . . . . . . . . . . . . . . . . . . .3-1Description . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . .3-2Power Distribution Center . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . .3-4Relay Bank . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . .3-5Instrumentation . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . .3-6Wiring Diagrams & Schematics . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . .3-8


SECTION PAGE

4 TRANSMISSIONTerminal Objective and Enabling Objectives . . . . . . . . . . . . . . . . . . . . . .4-1(Refer to RDS3000 Allison Transmission Manual)

5 FRONT AXLE & STEERINGTerminal Objective and Enabling Objectives . . . . . . . . . . . . . . . . . . . . . .5-1Introduction . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . .5-2Servicing . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . .5-4TAS Steering Gear . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . .5-5Front End Alignment . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . .5-19Disassembly, Overhaul and Assembly . . . . . . . . . . . . . . . . . . . . . . . . . .5-25

6 REAR AXLE & DURA RIDETerminal Objective and Enabling Objectives . . . . . . . . . . . . . . . . . . . . . .6-1Drive Axle . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . .6-2Removal . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . .6-2Inspection . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . .6-4Disassembly & Repair . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . .6-4Installation . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . .6-4Shock Absorbers . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . .6-7Description . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . .6-7Service . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . .6-8Inspection . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . .6-8Ride Height Check . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . .6-8Ride Height Adjustment . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . .6-11Rear Suspension . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . .6-12Leveling Valve Replacement . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . .6-13A-Frame Pivot Bearing Replacement . . . . . . . . . . . . . . . . . . . . . . . . . . .6-14

7 AIR SYSTEMTerminal Objective and Enabling Objectives . . . . . . . . . . . . . . . . . . . . . .7-1Operation . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . .7-2Schematic . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . .7-3Automatic drain . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . .7-4Air Brake System Tests . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . .7-5Brake Adjustment . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . .7-6Air Dryer . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . .7-8


SECTION PAGE

8 ABS/ATC SYSTEMTerminal Objective and Enabling Objectives . . . . . . . . . . . . . . . . . . . . . .8-1ABS Controller Introduction . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . .8-2Power Up Sequence . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . .8-3ABS Operation . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . .8-3ATC Operation . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . .8-4Troubleshooting ABS Controller . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . .8-5Troubleshooting Blink Codes & Diagnostic Modes . . . . . . . . . . . . . . . . . .8-7Troubleshooting Wiring . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . .8-22Glossary . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . .8-25Appendix A . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . .8-26

9 CHASSIS LUBRICATION SYSTEMTerminal Objective and Enabling Objectives . . . . . . . . . . . . . . . . . . . . . .9-1System Description . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . .9-2System Components . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . .9-2Air Operated Pump . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . .9-3Troubleshooting . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . .9-7

10 HYDRAULIC SYSTEMTerminal Objective and Enabling Objectives . . . . . . . . . . . . . . . . . . . . .10-1Description . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . .10-2Checking Oil Level . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . .10-3Hydraulic System Filters . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . .10-3Changing Hydraulic Oil . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . .10-3Hydraulic Relief Valve Adjustment . . . . . . . . . . . . . . . . . . . . . . . . . . . . .10-4Hydraulic System Repair . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . .10-6Hydraulic System Troubleshooting . . . . . . . . . . . . . . . . . . . . . . . . . . . .10-15

11 BOOM & FIFTH WHEELDescription . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . .11-1Servicing . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . .11-1Repair . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . .11-1Trailer Upper Coupler or Bolster Plates . . . . . . . . . . . . . . . . . . . . . . . . .11-6Troubleshooting . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . .11-7


SECTION PAGE

12 CAB LIFT SYSTEMTerminal Objective and Enabling Objectives . . . . . . . . . . . . . . . . . . . . .12-1Description . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . .12-2Servicing . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . .12-2Introduction . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . .12-6Alignment . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . .12-6Ride Height . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . .12-6Leveling Valve Operation . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . .12-6Cab Cushion Air Suspension System . . . . . . . . . . . . . . . . . . . . . . . . . . .12-6Troubleshooting Cab Lift Pump . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . .12-8

CAPACITY GENERAL INFORMATION

INTRODUCTIONThis manual contains information and instruc-tions for servicing, troubleshooting, mainte-nance and repair of the Trailer Jockey. Regularservicing and an established preventive main-tenance program will keep all components ofthe vehicle operating at maximum efficiencyand will promote a longer and safer service life.Follow the instructions in this manual carefullyto keep the vehicle operating properly.

SPECIFICATIONS:

ENGINEManufacturer . . . . . . . . . . . . . . . . . . . .Varies

TRANSMISSIONManufacturer . . . . . . . . . . . . . . ..........Varies

FRONT AXLEManufacturer . . . . . . . . . . . . . . . . . . . .Varies

REAR AXLEManufacturer . . . . . . . . . . . . . . ..........Varies

FRONT SUSPENSIONType . . . . . . . . . . . . . . . . . . . . . Leaf SpringsRating . . . . . . . . . . . . . . . . . . . . .13,200 Ibs.

REAR SUSPENSION Dura Ride Trailing Arm,Air Spring, 30,000 lb. ratingWHEELS22.5 X 8.35 Hub Piloted, 5-hole

CABWidth . . . . . . . . . . . . . . . . . . . . . . . . . . .51 in.Depth . . . . . . . . . . . . . . . . . . . . . . . . . .64 in.

HEATER45,000 BTU Fresh Air with Electric Blower

DEFROSTERType . . . . . . . . . . . . . . . . .Heater-integrated

DASH PANELRemovable for easy maintenance with volt-meter, hour meter, oil presure, air filter restric-tion indicator, water temperature, air systempressure, fuel level gauge.

WARNING DEVICES:Trailer ABS Fault Code . . . . . . . . . . . . .LightATC Automatic Traction Control Active .LightCharging System Indicator . . . . . . . . .LightLo-Air Air Pressure Low . . . .Light and AlarmEngine Major Fault Code . . . . . . . . . . . .LightWarning Minor Engine Fault Code . . . .LightWTS Wait to Start Warning . . . . . . . . . .LightComm J1939 Datalink Backbone failure LightTrans Temp exceeds parameters . . . . .LightCheck Trans Fault Code . . . . . . . . . . .LightRegen Icon Exhaust Regen. reqd. . . . .Light

CAB TILTING45° Hydraulically with 90° Tilt Capability

CAB MOUNTING . . . . . . . . .Rubber Cushion Front Cab Pivots . . . . . . . . . . . . . . .Safety Type Cab Latching

Rear Cab Air RideDOORSHeavy Duty Design with Key-Type Lock on L.H.and Rear Sliding Door .

HYDRAULIC SYSTEM FOR 5TH WHEELTrans. Direct Mounted Power Take-Off withDirect Mounted Gear Pump and 10 GallonReservoir

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FIFTH WHEEL & BOOM ASSEMBLY36” Dia. 5th wheel for 2” dia. king pins withCab-Controlled air unlatch and automaticrelatch

Dual hydraulic 5” double acting cylinders andself-aligning replaceable cylinder bushings.

TIRESFront . . . . . . . . . .Tubeless single 11 X R22.5 . . . . . . . . . . . . . .16 Ply LRG Highway Tread

Rear . . . . . . . . . . . .Tubeless Dual 11 X 22.5 . . . . . . . . . . . . . .16 Ply LRG Highway Tread

STEERINGHydraulic power steering with engine mountedgear driven pump

BRAKESFront axle . . . . . . . . . . . . . . . . . . . .ABS/ATVRear axle . . . . . . . . . . . . . . . . . . . . .ABS/ATCParking . . . . . . . . . .Spring type on rear axleEmergency . . . . . . . . . .Automatic application . . . . . . . . . . . . . . . . . . . . . .of parking brakes

COOLING SYSTEMFin and tube radiator of heavy duty constructionmounted on rubber shock pads. System sup-plied with 50% solution of permanent typeantifreeze with transmission oil cooler in lowerradiator tank.

FUEL TANK . . . . . . . . . .50 Gallon step tank

FILTERSEngine air . . . . . . . . . . . .Dry type air cleanerFuel (2) . . . . .Frame mounted fuel/water sep. . . . . . . . . . . . . . . . . . . . . . . .Engine mountedHydraulic pump . . . . . . . . . .Full flow spin-on . . . . . . . . . . . . . .element with intake strainerPower steering . . . . . .Replaceable cartridge . . . . . . .type within power steering reservoir

Engine Oil Filter . . . . . . . . . . . . . . . .SpinnerII

AIR SYSTEM15.2 CFM compressor, 3 tank reservoir system

ELECTRICAL SYSTEM12 Volt negative ground with circuit breakers,130 amp alternator, color coded wiring in sepa-rate removable harness.

STARTER . . . . . . . . . . . .Nippodensa Electric

BATTERY . . . . . . .Two12V 700CCA 31-ECO

EXHAUST . . . . .Converter muffler and outlet . . . . . . . . . . . . . . . . .with vertical behind cab

TRAILER EQUIPMENTAir . . . . . . . . . . . . . . . . . . . .Two air lines with . . . . . . . . . . . . . . . . . . . .glad hand receivers

Electrical . . . . . . . . .7-wire female receptacle . . . . . . . . . . . . . . . . . . . . . . . . .at rear of cab

VEHICLE LOAD CAPACITY (at 15 mph)GVW . . . . . . . . . . . . . . . . . . . . . . .32,200 lbs.GCVW . . . . . . . . . . . . . . . . . . . . .81,000 lbs.

WEIGHT (average) . . . . . . . . . . . .13,500 lbs.

TURNING RADIUS . . . . . . . . . .Standard 116” wheelbase 20’ 6”

DRAW BAR PULL . . . . . . . . . . . .12,702 lbs.

GRADEABILITY . . .At capacity GCW 15.9%

FIFTH WHEELLift Rating . . . . . . . . . . . . . . . . . . .70,000 lbs.Lift Height . . . . . . . . . . . . . . . . . . . . . . .16 in.

DIMENSIONSHeight . . . . . . . . . . . . . . . . . . . . . . . . .120 in.Width . . . . . . . . . . . . . . . . . . . . . . . . .98.8 in.Length . . . . . . . . . . . . . . . . . . . . . . . . .192 in.Wheelbase . . . . . . . . . . . . . . . . . . . . . .116 in.

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NOMENCLATURE

SPOT LIGHT

ENGINECOMPARTMENT

HYDRAULIC OILRESERVOIR

AUTO-GREASER

CAB TILT PUMPQUARTERFENDERS

DURA-RIDESUSPENSION

BATTERY BOX

AIR DRYER FIFTH WHEEL& BOOM

FUEL TANK

TILT CAB

FUEL FILTER


Maintenance Procedures

There are a number of procedures involved inmaintenance and repair that are referred tothroughout this manual. Application of theseprocedures will enable the technician to bemore efficient, better organized and capable ofperforming the various tasks properly, whichwill ensure that the service and/or repair is thor-ough and complete.

Fasteners

Fasteners are nuts, bolts, studs and screwsused to hold two or more parts together. Thereare a few things to keep in mind when workingwith fasteners. Almost all of them use a lockingdevice of some type, either a lockwasher, lock-nut, locking tab or thread adhesive. All thread-ed fasteners should be clean and straight, withundamaged threads and undamaged cornerson the hex head where the wrench fits.Develop the habit or replacing all damagednuts and bolts with new ones. Special locknutswith nylon or fiber inserts can only be usedonce. If they are removed, they lose their lock-ing ability and must be replaced.

Rusted nuts and bolts should be treated with apenetrating fluid to ease removal and preventbreakage. After applying the rust penetrant, letit work for a few minutes before trying to loosenthe nut or bolt. Badly rusted fasteners mayhave to be chiseled or sawed off or removedwith a special nut breaker, available at toolstores.

If a bolt or stud breaks off in an assembly, it canbe drilled and removed with a special tool com-monly available at tool stores.

Flat washers and lockwashers, when removedfrom an assembly, should always be replacedexactly as removed. Replace any damagedwashers. Never use a lockwasher on any softmetal surface (such as aluminum), thin sheetmetal or plastic.

Fastener Sizes

For a number of reasons, automobile equip-ment manufacturers are making wider andwider use of metric fasteners. Therefore, it isimportant to be able to tell the differencesbetween standard (sometimes called U.S. orSAE) and metric hardware, since they cannotbe interchanged.

All bolts, whether standard or metric, are sizedaccording to diameter, thread pitch and length.For example, a standard 1/2 - 13 x 1 bolt is 1/2inch diameter, has 13 threads per inch and is 1inch long. An M12 - 1.75 x 25 metric bolt is 12mm in diameter, has a thread pitch of 1.75 mm(the distance between threads) and is 25 mmlong. The two bolts are nearly identical, andeasily confused, but they are not interchange-able.

In addition to the differences in diameter, threadpitch and length, metric and standard bolts canalso be distinguished by examining the boltheads. To begin with, the distance across theflats on a standard bolt head is measured ininches. while the same dimension on a metricbolt is sized in millimeters (the same is true fornuts). As a result, a standard wrench shouldnot be used on a metric bolt and a metricwrench should not be used on a standard bolt.Also, most standard bolts have radial gradelines on the head to denote the grade orstrength of the bolt, which is an indication of theamount of torque that can be applied to it. Thegreater the number of grade lines, the greaterthe strength of the bolt. Metric bolts have aproperty class (grade) number, rather than radi-al lines, molded into their heads to indicatedbolt strength. In this case, the higher the num-ber, the stronger the bolt.

Strength markings can also be used to distin-guish standard hex nuts from metric hex nuts.Many standard nuts have dots stamped intoone side, while metric nuts are marked with anumber. the greater the number of dots, or the

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higher the number, the greater the strength ofthe nut.

Metric studs are also marked on their endsaccording to property class (grade). Largerstuds are numbered the same as metric boltswhile smaller studs carry a geometric code todenote property class.It should be noted that many fasteners, espe-cially grades 0 through 2, have no distinguish-ing marks on them. When such is the case, theonly way to determine whether it is standard ormetric is to measure the thread pitch or com-pare it to a known fastener of the same size.


Standard fasteners are often referred to asSAE, as opposed to metric. However, it shouldbe noted that SAE technically refers to a non-metric fine thread fastener only. Coarse threadnon-metric fasteners are referred to as USSsizes.

Since fasteners of the same size (both stan-dard and metric) may have different strengthratings, be sure to reinstall any bolts, studs ornuts removed in their original locations. Also,when replacing a fastener with a new one,make sure that the new one has a strength rat-ing equal to or greater than the original.

Tightening sequences and procedures

Most threaded fasteners should be tightened toa specific torque value (torque is the twistingforce applied to a threaded component such asa nut or bolt). Overtightening the fastener canweaken it and cause it to break, while under-tightening can cause it to eventually comeloose. Bolts, screws and studs, depending onthe material they are made of and their threaddiameters, have specific torque values. Besure to follow the torque recommendationsclosely. For fasteners not assigned a specifictorque, a general torque value chart is present-ed here as a guide. These torque values arefor dry (unlubricated) fasteners threaded intosteel or cast iron (not aluminum). As was pre-viously mentioned, the size and grade of a fas-tener determines the amount of torque that cansafely be applied to it. Higher grades can toler-ate higher torque values.

Fasteners laid out in a pattern, such as cylinderhead bolts, oil pan bolts, differential cover bolts,etc., must be loosened or tightened insequence to avoid warping the component.This sequence will normally be shown in theappropriate section. If a specific pattern is notgiven, the following procedures can be used toprevent warping.

Initially, the bolts or nuts should be assembled

finger tight only. Next, they should be tightenedone full turn each, in a criss-cross or diagonalpattern. After each one has been tightened onefull turn, return to the first one and tighten themall one-half turn, following the same pattern.Finally, tighten each of them one-quarter turn ata time until each fastener has been tightened tothe proper torque. Too loosen and remove thefasteners, the procedure would be reversed.

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TORQUE CHART

NOTE: This chart is intended as a guide for the wrench torque that should be applied to tighteningnuts and bolts or studs, or capscrews when no torque is specified on the assembly print or sepa-rate instructions.

When tightening a bolt with a castellated nut, torque to the low value shown on the chart. Then con-tinue to tighten until the hole in the bolt and the slot in the nut become aligned. Nuts must be of thesame SAE grade as the bolts on the chart. When nuts and bolts are of different grades, use thetorque value for the lower of the two.

This chart is not intended for use in seating a stud in a housing. These values were calculated onapproximately 75% of the proof-load for dry unplated bolts, and should be reduced by approximate-ly 25% for lubricated fasteners.


1-8


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Engine Dataplate

The engine data plates show specific informa-tion about your engine. The engine serial num-ber (1) and Control Parts List (CPL) (2) provideinformation for ordering parts and serviceneeds

NOTE: The engine dataplate must not bechanged unless approved by Cummins EngineCompany, Inc.

Transmission Nameplate

The transmission nameplate is located on theright rear side of the transmission. the name-plate shows the transmission serial number,part number (assembly number), and modelnumber. All three of these numbers must beprovided when ordering replacement parts orrequesting service information.

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Engine and Transmission Identification

CAPACITY PREVENTIVE MAINTENANCE

PRE-OPERATIONAL AND SAFETY INSPECTION

_______ Check engine oil level_______ Check engine coolant level_______ Check power steering fluid level_______ Check charge air cooler connections for security and leaks_______ Check hydraulic fluid level, boom down_______ Drain moisture from air tanks_______ Check tires for condition and proper inflation_______ Check cab holddown latches for proper operation_______ Check to ensure cab tilt pump selector is in cab lower position_______ Check cab door(s) for proper operation - ensure door latches operate properly_______ Check windshield wiper and washer for proper operation_______ Check accelerator for proper operation - accelerator must move freely through

range of operation_______ Check rear view mirrors and adjust as necessary_______ Inspect trailer hoses and electrical cable for security and condition_______ Clean all windows_______ Check neutral lockout system for proper operation_______ Check fifth wheel control lever for proper operation_______ Check fifth wheel secondary lock - lock should be disengaged_______ Check fifth wheel plate for proper lubrication_______ Check horn for proper operation_______ Check steering system for proper operation_______ Check all gauges/indicators for proper operation_______ Check parking and service brakes for proper operation_______ Check lube lever in auto lube system reservoir - if less than half, refill_______ Check fuel tank level - fill if necessary_______ Adjust seat as necessary_______ Check air compressor for proper operation - compressor cut-out pressure should

be 120 PSI - cut-in pressure should be between 90-110 PSI_______ Check electrical system for proper operaion - all lights acc. should be on_______ Check all lights for proper operation:

(a) Headlights, 1. High, 2. Low(b) Turn signals, 1. Right, 2. Left(c) Parking and clearance lights(d) Brake lights(e) Hazard lights

_______ Check transmission fluid level with engine running at idle_______ Perform final walk around inspection and check for (a) fluid leaks - engine,

transmission and axles. (b) air leaks, (c) check exhaust system for damage andleaks (d) check cab and frame for damage.

DAMAGE REPORT (Circle or markany damaged location)

Report all discrepancies to yoursupervisor

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SUGGESTED PREVENTIVEMAINTENANCE

DailyRecord hourmeter readingCheck coolant level and add coolant if neces-sary (Use caution)Check transmission oil level and add oil if nec-essary (engine running)Check engine oil level (engine stopped)Check power steering oil level and add oil ifnecessaryCheck all belts for tension and conditionCheck hydraulic oil level and add oil if neces-sary (boom down)Drain water from all air tanksCheck tire pressure and conditionCheck for leaks, broken or damaged partsCheck lights working and cleanCheck mirrors clean, tight and unbrokenCheck exhaust system for leaks or damageDrain Fuel/Water SeparatorCharge air connectionsTransmission filter indicators

Weekly or 50 Hours of OperationPerform all daily checksCheck auto lubeCheck oil in rear axle

200 Hours of OperationInitial change of RDS3000 main filter

Quarterly or 500 Hours of Operation

CAUTION - Never service air cleanerwith engine running to prevent dirt from beingdrawn into intake.

Service air cleaner when indicator shows redChange hydraulic oil filterCheck wheel nut torqueCheck fuel filters when fuel reaches 1/2” fromtop of clear bowlCheck adjustment on all brakesCheck air compressor mountingCheck charge air coolerCheck fuel pump mounting

Change engine oil and filerCheck wheel bearing oilCheck brake linings for wear and adjust camsor replace linings if necessaryCheck oil in rear axleCheck oil in transmission(Oil sampling analysis recommended)

DURA RIDE:Check center bearingCheck air bagsCheck height adjustment

2 Years or 2000 Hours of OperationCheck vibration damperCheck vibration damper rubberDrain and flush cooling system

3000 Hours of OperationChange internal transmission filter and changefluid(Oil sampling analysis recommended)Change steer reservoir filter and fluidChange hydraulic oil and clean strainerCheck air dryer cartridgeCheck and adjust 5th wheel jamsChange cab tilt pump fluidRepair FacilityCheck and clean automatic drain valves on airtank.

Engine Valve AdjustmentInitial valve adjustment at 5000 hours.Subsequent valve adjustments at 50,000 miles.Annual inspection or lube of hydraulic pumpand PTO shafts.

3 Years or 6000 Hours of OperationChange oil in rear axleChange oil in wheel bearingsChange oil in transmissionChange air dryer cartridgeChange brake linings


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Oil Level - Check

Never operate the engine with the oil levelbelow the “L” (Low) mark or above the “H”(High) mark. Wait at least 15 minutes aftershutting off the engine to check the oil. Thisallows time for the oil to drain to the oil pan.

NOTE: The vehicle must be level when check-ing the oil level to make sure the measurementis correct.

Coolant Level - Check

WARNING: Do not remove theradiator cap from a hot engine. Wait untilthe temperature is below 120˚ F. beforeremoving the pressure cap. Failure to do socan result in personal injury from heatedcoolant spray or steam. Remove the fillercap slowly to relieve coolant system pres-sure.

NOTE: Never use a sealing additive to stopleaks in the coolant system. This can result incoolant system plugging and inadequatecoolant flow causing the engine to overheat.The coolant level must be checked daily.

Daily Maintenance Procedures

General Information

Preventative maintenance begins with day-to-day awareness of the condition of the engine and itssystems. Before starting the engine, check the oil and coolant levels. Look for:

• Leaks• Loose or damaged parts• Worn or damaged belts• Any change in engine appearance

CAUTION: Do not add coldcoolant to a hot engine. Engine castings canbe damaged. Allow the engine to cool to below120˚ F. before adding coolant.

Fill the cooling system with coolant to 1” belowthe bottom of the fill neck in the radiator fill.


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Drive Belt - Inspection

Visually inspect the belt. Check the belt forintersecting cracks. Transverse (across thebelt width) cracks are acceptable. Longitudinal(direction of belt length) cracks that intersectwith transverse cracks are not acceptable.Replace the belt if it is frayed or has pieces ofmaterial missing.

Cooling Fan - Inspection

Warning. Personal injury can resultfrom a fan blade failure. Never pull or pryon the fan. This can damage the fanblade(s) and cause fan failure.

NOTE: Rotate the crankshaft by using theengine barring gear.

A visual inspection of the cooling fan is requireddaily. Check for cracks, loose rivets, and bentor loose blades. Check the fan to make sure itis securely mounted. Tighten the capscrews ifnecessary. Replace any fan that is damaged.


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Maintenance Procedures - 250 Hours or 3 Months

General Information

All checks or inspections listed under daily or previous maintenance intervals must also be per-formed at this time in addition to those listed under this maintenance interval.

Air Intake System - Inspection

Inspect the intake piping for cracked hoses,loose clamps, or punctures which can allow dirtand debris to enter the engine.

Tighten or replace parts as necessary to makesure the air intake system does not leak.


2-6

Maintenance Procedures - 500 Hours of Operation

• Check wheel bearing oil• Check brake linings for wear and adjust cams or replace linings if necessary• Check oil in rear axle• Check oil in transmission

(Oil sampling analysis recommended)

Lubricating Oil and Filter ChangeInterval

The maximum recommended oil and filterchange intervals are 250 hours or 3 months;whichever comes first. If your application accu-mulates high hours and low mileage, thechange interval is determined by hours.

Fill the engine with clean oil to the proper level.

Pan Capacity - 15 U.S. QuartsTotal System Capacity - 17.3 U.S. Quarts

Operate the engine at idle to inspect for leaksat the filters and the drain plug.

Stop the engine. Wait approximately 15 min-utes to let the oil drain from the upper parts ofthe engine. Check the oil level again.

Add oil as necessary to bring the oil level to the“H” (High) mark on the dipstick.


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STEER AXLE

Description

This steer axle is of extremely rugged construc-tion. The design prevents scuffing of the steertires.

Lubrication

Access for checking proper lubrication cab beattained by steering the machine first to oneside and then to the other. Lubrication isaccomplished by the automatic lubrication sys-tem which is determined by the timer adjust-ment.

Refer to the Recommended Lubrication Chartfor type of lubricant to be used. If the machineis subjected to heavy work schedule underextreme dusty conditions, more frequent lubri-cation may be necessary.

Front Wheel Bearings Lubrication(Oil lubricated)

Hub caps used with oil lubricated front wheelbearings may be removed in the same manneras conventional hub caps. Care must be takento correctly install gasket since oil leakage canoccur at this point. Bolts should be torquedevenly to 24 ft lbs.

Adding Lubricant

The correct oil level for the front wheel bearingsis at the oil level line. It is permissible for the oillevel to be up to 1/4 inch above the oil level line.The vehicle must be level.

When adding lubricant to front wheel hubs, waita short period of time for the lubrication to seekits level. Recheck the lubricant level, add morelubricant if necessary, and replace the fillerplug. Use lubricant as specified in section 1

Front Wheel Bearing Service

Wheel bearings must be correctly adjusted formaximum bearing life. Perform the followingprocedures to service and adjust the frontwheel bearings.

a. Removal

1. Install wheel chocks on rear wheelsto prevent movement, then place a jack underthe front axle and raise until the tire lifts off theground. Remove the wheel.

2. Remove the capscrews (1) a n dwashers (2) from the hub cap (3).

Front Axle

Oil Lubricated Hub Cap


2-8

100 to 150 ft. lbs. Torque 2-5/8” and larger jamnuts 100 to 200 ft. lbs. The resulting end playmust be within limits of .001 to .010 in. loose.

6. Install hub cap (3) and gasket (4),and secure with capscrews (1) and lockwash-ers (2). Install wheel.

7. Install brake drum (10).

8. Install wheel then torque wheel nutsto specified value.

3. Remove hub cap (3) and gasket (4).

4. Remove outer bearing nut (5), lock-washer (6) and lockwasher (7).

5. Remove inner bearing adjuster nut(8).

6. Remove outer bearing cone (9).

7. Remove drum (10) and hub assem-bly (11).

8. Remove seal assembly (12) andinner bearing cone (13).

b. Cleaning and Inspection.

1. Clean bearings, hub and seal.

2. Inspect the parts for wear or damage,making any necessary replacements.

3. Coat bearings with synthetic gearlube 75W-90.

c. Installation and Adjustment.

1. Install the inner cone (13) and sealassembly (12) in the hub (11) using a properseal installation tool and place the hub on thefront spindle.

2. Install the outer cone (9).

3. Install inner adjusting nut (8). Threadthe nut against the bearing as the hub assem-bly is revolved.

4. Using a torque wrench, tighten theadjusting nut to 50 ft. lbs. torque while rotatingdrum and hub assembly in both directions to besure all bearing surfaces are in contact.

5. Back off adjusting nut 1/6 to 1/4 turn.Install lockwasher (7), lockwasher (6) and outerjam nut (5). Torque 1-1/8” to 2-5/8” jam nuts

Front Wheel Bearings


2-9

DRIVE AXLEDescription

This axle is a heavy duty type with doublereduction gearing. Positive full flow lubricationassures adequate lubrication to all movingparts of the carrier under all operating condi-tions.

Checking Oil Level

Perform the following procedures to check oillevel and service the differential.

NOTE

The machine should be parked on a level sur-face when the drive axle is being serviced.Refer to the Lubrication Chart for servicingintervals and type of oil to be used.

a. Provide a suitable container to catchoil then remove drain plug.

b. Once oil has completely drained, rein-stall drain plug.

c. Service differential with specified oilthrough Fill/Level plug hole until oil starts toflow from the hole.

d. Install Fill/Level plug.

e. Wipe away any excess oil from axlehousing then dispose of used oil in accordancewith federal and local regulations.

DRIVE AXLEDescription

This axle is a heavy duty type with doublereduction gearing. Positive full flow lubricationassures adequate lubrication to all movingparts of the carrier under all operating condi-tions.

Checking Oil Level

Perform the following procedures to check oillevel and service the differential.

NOTE

The machine should be parked on a level sur-face when the drive axle is being serviced.Refer to the Lubrication Chart for servicingintervals and type of oil to be used.

a. Provide a suitable container to catchoil then remove drain plug.

b. Once oil has completely drained, rein-stall drain plug.

c. Service differential with specified oil

Rear Wheel Bearings


and seals must be manually supplied with ade-quate lubricant or they will be severely dam-aged before the normal motion of the vehiclecan supply lube to the hub ends of the housing.

To avoid the risk if premature damage to wheelbearings and seals, they must be “prelubed”any time the wheel equipment is beinginstalled.

1. Fill axle with lube through axle housingcover filler hole.

2. Jack up left side of axle. Maintain this posi-tion for one minute to allow lube to flow intowheel ends at right side.

3. Jack up right side of axle. Maintain this posi-tion for one minute to allow lube to flow intowheel ends at left side.

4. With vehicle level again, add lube throughaxle housing cover filler hole The axle shouldrequire two additional pints of lube to bring levelup to bottom of filler hole.

Rear Wheel Bearing Service

Wheel bearings must be correctly adjusted toachieve maximum bearing life. Perform the fol-lowing procedures to service and adjust therear wheel bearings.

a. Removal.

1. Install wheel chocks to prevent move-ment then place a jack under the rear axle andraise until the tires lift off the ground. Adjustbrake shoes until there is no drag on thewheels.

2. Remove the nuts (1) to remove thewheels and drum (2).

3. Place a suitable container under theend of the axle to catch lubricant.

4. Remove the nuts (3), lockwashers(4), axle shaft (5), gasket (6), outer seal (7),gasket (8) and wiper (9).

5. Remove the nut (10), lockwasher(11), nut (12) and bearing cone (13).

6. Carefully pull the hub (14) from theaxle housing (19).

7. Remove the seal (15) and bearingcone (16). Remove the bearing cups (17 and18) only if they require replacement.

b. Cleaning and Inspection

1. Clean old lubricant from bearings,hub and seals.

2. Inspect the parts for wear or damage,making any necessary replacements. Repackthe hub and bearings with manufacturer’s spec-ified lubricant.

c. Installation and Adjustment.

1. If bearing cups (17 and 18) wereremoved, install the bearing cups making surethey are seated squarely in their bores.

2. Install the bearing cone (16) andgrease seal (15) then, slide the hub (14)assembly onto the axle housing (19).

3. Install the bearing cone (13) and nut(12). Thread the adjusting nut against the bear-ing as the hub is rotated.

4. Tighten nut (12) to 50 ft. lbs. torquewhile rotating the hub in both directions. Thewheel should turn easily.

5. Install spindle washer (11) engagingnut dowel pin with hole in washer.

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NOTE

If dowel pin and washer hole are not aligned,remove washer, flip over and reinstall. For fur-ther alignment, the nut can be moved slightly.However, do not back off more than 1/3 turn.

6. Repeat rotation of the wheel in bothdirections. The wheel should rotate freely andbe within limits of 0.001” (.020 mm) end play.

7. With adjustment complete, installouter nut and torque to 300-400 ft. lbs.

8. Install gasket (8), outer seal (7), gas-ket (6), wiper (9) and axle shaft (5). Securewith lockwashers (4) and nuts (3).

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2-12

Maintenance Procedures at 5000 Hours or 1 Year

General Information

All checks or inspections listed under daily or previous maintenance intervals must also be per-formed at this time in addition to those listed under this maintenance interval.


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Maintenance Procedures at 2000 Hours or 2 Years

Cooling System Maintenance -Coolant Draining

CAUTION: Avoid prolongedand repeated skin contact with usedantifreeze. Such prolonged repeated con-tact can cause skin disorders or other bod-ily injury.

• Avoid excessive contact - wash thorough-ly after contact.

• Keep out of reach of children

Protect the environment: Handling and dis-posal of used antifreeze can be subject tofederal, state, and local law regulation. Useauthorized waste disposal facilities, includ-ing civic amenity sites and garages provid-ing authorized facilities for the receipt ofused antifreeze. If in doubt, contact yourlocal authorities or the EPA for guidance asto proper handling of used antifreeze.

Drain the cooling system by opening the drainvalve on the radiator and removing the plug inthe bottom of the water inlet. A drain pan witha capacity of 10 U.S. gallons will be adequatein most applications.

Check for damaged hoses and loose or dam-aged hose clamps. Replace as required.Check the radiator for leaks, damage and buildup of dirt. Clean and repair as required.


2-17

Cooling System Flushing

CAUTION: During filling, airmust be vented from the engine coolant pas-sages. The air vents through the “jiggle pin”openings to the top radiator hose and out the fillopening.

NOTE: Adequate venting is provided for a fillrate of 5 U.S. gallons/minute.

Fill the system with a mixture of sodium carbon-ate and water (or a commercially availableequivalent).

NOTE: Use 1.0 pounds of sodium carbonatefor every 6 U.S. gallons of water.

CAUTION: Do not install theradiator cap. The engine is to be operatedwithout the cap for this process.

Use a mixture of 50 percent water and 50 per-cent propylene glycol antifreeze to fill the cool-ing system.

CAUTION: Never use wateralone for coolant. Damage from corrosioncan be the result of using water alone forcoolant.

Install the pressure cap. Operate the engineuntil it reaches a temperature of 180˚ F. andcheck for coolant leaks.

Check the coolant level again to make sure thesystem is full of coolant.

WARNING: Before removingthe pressure cap, wait until the coolant tem-perature is below 120˚ F. Failure to do socan cause personal injury from heatedcoolant spray.


2-18

Vibration Damper (Rubber) -Inspection

Check the index lines (A) on the damper hub(B) and the inertia member (C) If the lines aremore than 1/16 inch out of alignment, replacethe damper.

Inspect the rubber member for deterioration. Ifpieces of rubber are missing or if the plasticmember is more 1/8 inch below the metal sur-face, replace the damper.

NOTE: Also look for forward movement of thedamper ring on the hub. Replace the damper ifany movement is detected.

Air Compressor - Inspection

NOTE: All air compressors have a smallamount of lubricating oil carry over which lubri-cates the piston rings and moving parts. Whenthis lubricating oil is exposed to normal air com-pressor operating temperatures over a periodof time, the lubricating oil will form varnish orcarbon deposits. If the following inspectionsare not done, the air compressor piston ringswill be affected by high operating temperaturesand pressures and will not seal correctly.

Air Compressor Discharge Inspection

Drain the air system wet tank to release thesystem air pressure. Remove the air dischargeline from the air compressor.

Measure the total carbon deposit thicknessinside the air discharge line as shown. If thetotal carbon deposit (X + X) exceeds 1/16 inch,clean and inspect the cylinder head, the valveassembly, and the discharge line. Replace ifnecessary.


2-19

If the total carbon deposit exceeds specifica-tions, continue checking the air discharge lineconnections up to the first tank until total car-bon deposit is less than 1/16 inch. Clean orreplace any lines or connections that exceedthis specification.

Inspect air dryer, spitter valves and pressurerelief valves for carbon deposits or malfunction-ing parts. Inspect for air leaks.


2-20

RECOMMENDEDLUBRICANTS ANDCAPACITIES

ENGINE OIL . . . . . . . . . . . . . . . . . . .17.3 qts. . . . . . . . . . . . . . . SAE 15W40 - Heavy Duty . . . . . . . . . . . . . . . . . . . . . . . . . . .(API C1-4)

TRANSMISSION OIL . . . . . . . . . . . . .23 qts. . . . . . . . . . . . . .Synthetic Transmission Fluid . . . . . . . . . . . . . . . . . . . . . .Castrol Transynd

DRIVE AXLES OIL . . . . . . . . . . . . . . .41 pts. . . . . . . . . . . . . .Synthetic Gear Lube 75W-90 . . . . . . . . . . . . . . . . . . . . . . . . .Chevron RPM

POWER STEERING . . . . . . . .4 Qt. “Dexron” . . . . . . . . . . . .Automatic Transmission Fluid

HYDRAULIC SYSTEM . . . . . . . . . . . .10 Gal. . . . . . . . . . . . . .Anti-Wear, AntiFoam (AW46)

FUEL TANK . . . . . . . . . . . . . . . . . . . .50 Gal. . . . . . . . . . . . . . . . . . . . . . .No. 2 Diesel Fuel

CHASSIS FITTINGS . . . . . .NLGI-00 Grease

AUTO LUBE PUMP RESERVOIR . . . .6 Lbs.

FRONT WHEEL BEARINGS . . . . . . . . . . . . . . . . . . . . . . . . . .Synthetic Gear Lube 75W-90 . . . . . . . . . . . . . . . . . . . . . . . . .Chevron RPM

CAB TILT PUMP . . . . . . . .2 Qts. Dextron III . . . . . . . . . . . .Automatic Transmission Fluid

COOLING SYSTEMRECOMMENDATIONS

41 Qt. - Use 50/50 solution of Ethylene Glycolpermanent antifreeze and softened water inwinter.

TIRE PRESSURE MAXIMUMRECOMMENDED

FRONT . . . . . . . . . . . . . . . .11R X 22.5-16PR . . . . . . . . . . . . . . . . . . . . . . . . . . . . .105 PSI

REAR . . . . . . . . . . . . . . . . .11R X 22.5-16PR . . . . . . . . . . . . . . . . . . . . . . . . . . . . . .95 PSI

FUEL REQUIREMENTS

GENERAL FUEL CLASSIFICATIONWinter . .No. 1-D or 2-D Blended (Winterized)Summer . . . . . . . . . . . . . . . . . . . . . . .No. 2-D

FINAL BOILING POINT . . . . . . . . . . . . . . . . . . . . . . . . . .675˚ F. Max.

CETAIN NO.Winter . . . . . . . . . . . . . . . . . . . . . . . . .45 Min.Summer . . . . . . . . . . . . . . . . . . . . . . .40 Min.

SULFUR CONTENT . . . . . . . . . .05% Max.


2-21

ALL CHANGE PERIODS OUTLINED IN SECTION 1 ARE RECOMMENDATIONSBASED ON AVERAGE CONDITIONS. LUBRICANTS SHOWING SIGNS OFEXCESSIVE HEAT, OXIDATION OR DIRT, SHOULD BE CHANGED OFTENENOUGH TO PREVENT THESE CONDITIONS FROM OCCURRING. CHANGEPERIODS MUST BE ESTABLISHED ON THE BASIS OF INDIVIDUAL JOB CONDI-TIONS.

CAPACITY ELECTRICAL SYSTEM

TOPIC 3 – ELECTRICAL SYSTEM

Terminal Objective:

Upon completion of this unit, the student will be knowledgeable in the location, identifica-tion, procedures, diagnostics and repairs of the electrical system found on Capacity spot-ters.

Enabling Objectives:

• Locate, identify and define wire coding, usage, and circuit protection. Identify andrepair electrical connectors and terminals used on these vehicles.

• Read and interpret vehicle wiring diagrams. Identify, locate and trace circuitsusing the vehicle wiring diagrams.

• Locate and identify the electrical system components, harnesses, electrical panels,bulkhead connectors, electronic control modules and other related componentsused on these vehicles.

• Understand the operation and diagnosis of circuit protection devices used onthese vehicles.

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3-2

DESCRIPTION

The electrical system consists of a battery, abattery charging alternator with voltage regula-tor, ignition and starter switch, starter, anddiaphragm valve. The remainder of the electri-cal system consists of instruments, switches,sending units, wiring, circuit breakers, etc., nec-essary for operation of the electrical system.Equipment selected by the customer will deter-mine the electrical equipment to be installed inaddition to the standard electrical system.

Battery

There are two 12V 700CCA 31-ECO batteries.They are maintenance-free. Water does nothave to be added at any time. If a maintenancetype battery is installed at any time, the waterlevel should be checked periodically.

CAUTION

Overfilling can cause poor performance or earlyfailure.

a. Keep the top of the batteries, termi-nals and cable clamps clean. When necessary,wash them with a solution of baking soda andwater, and rinse with clean water.

CAUTION

Do not allow the soda solution to enter thecells.

b. Inspect the cables, clamps and hold-down brackets regularly. Replace any damagedparts. Clean and re-apply a lightcoating of grease to the terminals and cableclamps when necessary.

c. Check the electrical system if the bat-tery becomes discharged repeatedly.

d. Use the following quick in-the-unitcheck as an indication of faulty components in

the battery charging circuit

(1 ) A fully charged battery and lowcharging rate indicates normal alternator-regu-lator operation.

(2) A low battery and high charging rateindicates normal alternator-regulator operation.

(3) A fully charged battery and a highcharging rate usually indicates the voltage reg-ulator is not limiting the alternator output.

CAUTION

A high charging rate on a fully charged batterywill damage the battery and other components.

(4) A low battery and low or no chargingrate could be caused by loose connections,damaged wiring, defective alternator, improperregulator operation, or defective alternator.

NOTE

If the machine is to be inoperative or idle formore than 30 days, remove the batteries. Thebatteries should be stored in a cool dry place.

Alternator

The alternator can be expected to give long,trouble-free service; however, the diodes andtransistors in the alternator circuit are very sen-sitive and can be easily destroyed. The follow-ing precautions should be observed whenworking on or around the alternator.

Avoid grounding the output wires or the fieldwires between the alternator and regulator.

Never run an alternator on an open circuit.

Grounding an alternator's output wire or termi-nals, which are always hot regardless ofwhether or not the engine is running and acci-dentally reversing the battery's polarity will


3-3

destroy the diodes. Grounding the field circuitwill also result in the destruction of the diodes.Some voltage regulators provide protectionagainst some of these circumstances; however,it is recommended that extreme caution beused.

Accidentally reversing the battery connectionsmust be avoided. If a booster battery is to beused, the batteries must be connected positive(+) to positive (+), and negative (-) to negative(-).

Never disconnect the batteries while the alter-nator is in operation. Disconnecting the batter-ies will result in damage to the diodes, causedby the momentary high voltage and currentinduced by the instantaneous collapse of themagnetic field surrounding the field windings.

NOTE

Cummins engines use an automatic springloaded belt tensioner on the water pump andalternator belt. No belt tension adjustment isnecessary on this belt.

Drive Belt Tension - Check

Measure the belt deflection at the longestspan of the belt.

Maximum deflection: 3/8 to 1/2 inch.


Power Distribution Center

1 Electronic Board Assembly2 Flasher onlyNS Flasher bracket

2

3-4


Relay Bank

1 105 amp man reset breaker . . . . . . . . . . . . . . . . . . . . . . . . . . .42 75 amp relay with diode . . . . . . . . . . . . . . . . . . . . . . . . . . .33 12V solenoid . . . . . . . . . . . . . . . . . . . . . . . . . . .2

1

3

2

3

3-5


Item No. Name Function

1 Voltmeter Indicates current within electrical system

2 Hourmeter Indicates total time the engine has beenoperating in hours and tenths of hours.This is vital to good maintenance proce-dures and to keep records on theTrailer Jockey

3 Engine Oil Pressure Indicates pressure within engine lubri-Gauge cation system in PSI and KPa. Normal

reading 40 to 60 PSI.

4 Engine Water Temperature Indicates temperature of engine coolant indegrees F. and Celsius. Normal operatingtemperature 170˚-195˚ F.

5 Air Filter Restriction Indicates need to change air filter.Indicator

6 Emergency Flasher Pull knob out to activate emergency flashers.Control Push knob in to deactivate.

7 Turn Signal/High Beam Move lever FORWARD to indicate rightControl turns, or BACK to indicate left turns.

Lift lever to switch from low to high beams,lift again to switch back to low beam

1

2

3 45

67

INSTRUMENTATION

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Item No. Name Function

8 Horn Button Depress in center of steering wheel to soundhorn.

9 Air System Pressure Indicates pressure within air brake systemGauge in PSI and KPa. Normal maximum operating

pressure is approximately 120 PSI. A warningbuzzerwill sound if air pressure drops below 60 PSI.

10 Speedometer Indicates speed vehicle is traveling in milesper hour and kilometers per hour.

11 Fuel Level Gauge Indicates level of fuel remaining in fuel tank.

12. Ignition Switch Key operated, 3 position switch.Anti-Restart OFF position - electrical system de-energized

key can be removed.ON position - electrical system energized.START position - spring loaded position.This position engages and activates theengine starter motor. When key is released,switch will return to ON position.Key must be turned to OFF positionbefore trying to restart again.

8

9

10 11

12

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WIRING DIAGRAMS

Since it isn’t possible to include all wiring infor-mation on one wiring diagram, smaller individ-ual wiring diagrams are provided for clarity.

Prior to troubleshooting any electrical circuitcheck the circuit breaker to make sure they arein good condition. Make sure that the battery isproperly charged and that the battery cableconnections are clean and in good condition.When checking a wiring circuit, make sure thatall connectors are clean with no broken orloose terminals. When unplugging a connec-tor, do not pull on wires. Pull only on the con-nector housings themselves.

Electrical Troubleshooting - GeneralInformation

A typical electrical circuit consists of an electri-cal component, switches, relays and circuitbreakers related to that component and thewiring and connectors that link the componentto both the battery and the chassis. To helppinpoint an electrical circuit problem, wiring dia-grams are included in this section.

Before tracking any troublesome electrical cir-cuit, first study the appropriate wiring diagramto get a complete understanding of what makesup that individual circuit. Trouble spots, forinstance, can often be narrowed down by not-ing if other components related to the circuit areoperating properly. If several components orcircuits fail at the same time, chances are theproblem is in the circuit breaker or ground con-nection.

Electrical problems usually stem from simplecauses, such as loose or corroded connec-tions, bad relay and/or circuit breaker. Visuallyinspect the condition of circuit breakers, wiringand connections in the problem circuit beforetroubleshooting it.

If testing instruments are going to be utilized,use the wiring diagrams to plan ahead of timewhere you will make the necessary connec-tions in order to accurately pinpoint the troublespot.

The basic tools needed for electrical trou-bleshooting include a circuit tester or voltmeterand a continuity tester.

Voltage Checks

Voltage checks should be performed in a circuitthat is not functioning properly. Connect onelead of a circuit tester to either the negative bat-tery terminal or a known good ground. Connectthe other lead to a connector in the circuit beingtested. If the bulb in the tester lights, voltage ispresent, which means that part of the circuit isproblem free. Continue checking the rest of thecircuit in the same fashion. When you reach apoint at which no voltage is present, the prob-lem lies between that point and the last testpoint with voltage. Most often the problem canbe traced to loose or bad connections.

NOTE: Keep in mind that some circuits receivevoltage only when the ignition switch is in therun position.

Locating a Short

One method of finding a short in a circuit is toremove the circuit breaker and connect a testlight or voltmeter to the breaker terminal. Thereshould be no voltage present in the circuit.Move the electrical harness from side to sidewhile watching the test light. If the light comeson, there is a short to ground somewhere inthat area, probably where the insulation hasrubbed through. The same test can be per-formed on each component in the circuit includ-ing the switch.

3-8


Ground Check

Perform a ground test to check whether a com-ponent is properly grounded. Disconnect thebattery and connect one lead of a self poweredtest light or continuity tester to a known goodground. Connect the other lead to the wire orground connection being tested. If the lightcomes on, the ground is good. If the light doesnot come on the ground is bad.

Continuity Check

A continuity check is done to determine if thereare any breaks in a circuit. With the circuit off(no power in the circuit) a self powered continu-ity tester can be used to check the circuit.Connect the test leads to both ends of the cir-cuit (or to the “power” end and a good ground)and if the test light comes on the circuit is pass-ing current properly. If the test light does notcome on, there is a break somewhere in the cir-cuit. This same procedure can be used to testa switch, by connecting the continuity tester tothe switch terminals. With the switch turned on,the test light should come on.

Finding an Open Circuit

When diagnosing for possible open circuits, it isoften difficult to locate them by sight becauseoxidation or terminal misalignment are hiddenby the connectors. Merely wiggling a connec-tor on a sensor or in the electrical harness maycorrect the problem. Remember this when anopen circuit is indicated when troubleshooting acircuit. Intermittent problems may also becaused by oxidation or loose connections.

Electrical troubleshooting is simple if you keepin mind that all electrical circuits are basicallyelectricity running from the battery, through thewires, switches, relays and circuit breaker toeach electrical component (light bulb, motor,etc.) and to ground, from which it is passedback to the battery. Any electrical problem is aninterruption in the flow of electricity to and fromthe battery

3-9

CAPACITY TRANSMISSION

TOPIC 4 – ALLISON TRANSMISSION(Refer to Allison RDS3000 Allison Transmission Manual)

Terminal Objective:

Upon completion of this unit, the student will be knowledgeable in the identification, con-struction, operation, diagnostics, troubleshooting and repairs of the ALLISON RDS-3000Transmission found on Capacity spotters.


• Identify the Allison transmission and identify it as an assembly or in componentsform.

• Understand basic operation, locate external and internal electronic components,decode Identification Plate and identify fluid levels.

• Identify components of the cooling system.• Understand electronic controls and operation such as inputs, outputs, TCM and

J1939.• Perform system diagnostics and troubleshooting.

4-1

CAPACITY FRONT AXLE & STEERING

TOPIC 5 – FRONT AXLE & STEERING

Terminal Objective:

Upon completion of this unit, the student will be knowledgeable in the identification, pro-cedures and repairs of the front axle & steering system found on Capacity spotters.


• Identify the TAS steering and identify it as an assembly or in components form.• Understand basic operation, procedures for tow-in adjustments, axle stops and

components of the steering column.

5-1


INTRODUCTION

The following paragraphs outline the proce-dures to remove and replace various compo-nents of the hydraulic power steering system.Each of the components may be serviced indi-vidually. Perform only the steps necessary toeffect the desired repair. Refer to the figures asindicated for location and identification of partswhile performing these procedures.

NOTE:

Many power steering problems are due to lackof pressure or insufficient flow. In the event anyproblem occurs, always check first for low oillevel, restricted lines, loose fitting and pluggedfilters. Use the following procedures to testpressure and flow. (See “Steering CircuitHydraulic Tests” illustration, Figure 11-1)

1. Install a pressure gauge and a shut off valvein the line from the pump outlet to gear inlet.Install a flow meter in the line from the gear out-let to reservoir. Place a thermometer in thereservoir.

2. With the shut off valve open, start the engineand steer the wheels to lock several times toheat the system fluid to approximately 130˚ F.

3. Steering Pump Pressure Test.

a. Operate the engine at approximately1000 RPM.

NOTE: Test at 1000 RPM. Pump flow (nopressure) should be 4.5 GPM +/- .5 GPM.Pump flow (at 1000 PSI) should be 4.0 GPM.Relief pressure 1300 PSI (no flow).

CAUTION

Do not keep the shut off valve closed over fiveseconds to avoid damage to the pump.

b. Close the shut off valve and read thepressure gauge.

c. If the pressure is below 1250 PSI orabove 2000 PSI, repair or replace the pump.

NOTE:

Closing of the valve will cause the fluid temper-ature to increase significantly. Allow the fluid tocool to 130˚ F. before continuing tests.

4. Steering Pump Flow Test.

a. Operate the engine at idle speed andslowly close the shut off valve until the pressuregauge indicates 1000 PSI. Record the flowrate shown on the flow meter. (Min. 3 GPM,Max 8 GPM) Open the shut off valve.

NOTE:

If fluid temperature has risen, allow it to cool to130˚ F.

b. Increase engine speed to 1200 -1300 RPM. Read and record the flow rate.Slowly close the shut off valve until the pres-sure gauge reaches 1000 PSI and again recordthe flow rate.

c. The reduction from the first reading tothe second reading should not exceed 20%.

5. Steering Gear Internal Leakage Test.

a. Place a long steel spacer block (1inch square by 6 inches long) between the axlestops as shown (see illustration “InternalLeakage Test” , Figure 11-2)

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5-3

Figure 11-1

PUMP FLOW RATE VS ALLOWABLEINTERNAL LEAKAGE

VARIOUS SPEEDS OF STEERING AS NOTED

FOR 2 HWT/SEC

FOR 1.5 HWT/SEC

FOR 1.0 HWT/SEC

FLOW RATEFROM PUMP@ 1000 PSI& ENGINEIDLE (GPM)130˚ F.

F = FAHRENHEITGPM = GALLONS PER MIN.HWT = HAND WHEEL TURNSPSI = POUNDS PER SQ. IN.

ALLOWABLE INTERNAL LEAKAGE (GPM)@ STEERING GEAR 130˚ F.

Figure 11-2 Figure 11-3


5-4

b. Turn the steering wheel until the linkage bot-toms out on the spacer block.

NOTE:

Apply at least 20 lbs. to the rim of the steeringwheel during this test to be sure the steeringgear control valve is closed.

c. Pressure gauge should now read sys-tem relief pressure as noted in pump pressuretest. Steering gear internal leakage can beread on the flow meter.

CAUTION

Do not hold the steering wheel in the maximumturn position longer than five to ten seconds ata time to avoid pump damage.

d. If leakage is greater than 1.5 GPMthe gear should be repaired or replaced. Ifleakage is less, refer to the “Allowable LeakageChart” below to determine the allowable leak-age. Use the flow rates recorded during pumpflow tests. (Figure 11-3)

e. Repeat procedure for opposite direc-tion of turn.

SERVICING

a. Maintain the proper level of fluid in thereservoir.

b. Check all hoses and fittings for sign ofleakage.

c. The power steering filter requires peri-odic replacement. Refer to the PeriodicMaintenance Chart for the intervals betweenpower steering filter changes.

d. Change the power steering filter byperforming the following:

(1) Refer to Figure 11-4 and remove thewingnut (1) and gasket (3) to release the cover(4) and gasket (5).

(2) Remove the spring (6) and cap (7) torelease the filter element (8).

(3) Position the replacement filter ele-ment (8) place in the reservoir (9) then, installcap (7) and spring (6).

(4) Install the gasket (5), cover (4), gas-ket (3) and wing nut (1).

CAUTION

Do not mix power steering fluids. Seal damagemay result.

(5) Fill the reservoir to the FULL mark onthe dipstick (2) with the grade of oil listed in theRecommended Lubricants chart in the front ofthis manual.

Figure 11-4


5-5

TAS STEERING GEAR

General Operation

What Happens During a SteeringManeuver

When the driver turns the steering wheel, hetransmits force from the steering wheel to thesteering gear input shaft. A torsion bar, pinnedat its one end to the input shaft and at its otherend to the worm shaft, turns with the input shaftand exerts a rotational force on the worm shaft.In response to this rotational force, the wormshaft, acting through the recirculating ballmechanism, tries to move the rack piston axial-ly through the gear housing cylinder bore.

The rack piston’s axial movement is resisted byits engagement to the sector shaft, which isconnected by linkage to the steered wheels.Because of this resistance, the torsion bar istwisted by the input shaft, thereby actuating thecontrol valve. Pressurized fluid, directed by thecontrol valve, assists in moving the rack pistonaxially through the cylinder bore. The rack pis-ton then turns the sector shaft to steer the vehi-cle.

Shock Loads to the Gear

If the steered wheels receive a shock load, theshock forces are transmitted through the sectorshaft to the rack piston, and on to the wormshaft. The internal geometry of the steeringgear causes the control valve to send high-pressure fluid to the correct cylinder cavity toresist the shock forces. By absorbing the shockforces hydraulically, the steering gear preventsobjectionable kickback at the steering wheel.

Unloading (Poppet) Valves

The steering gear is equipped with two unload-ing valves, one at each end of the rack piston.

One valve or the other, depending on the direc-tion of turn, will trip as the steered wheelsapproach the axle stops (which must be setaccording to manufacturer's specification). Thetripped valve reduces pressure in the gear andhelps to reduce heat generated by the pump. Atthe same time, the valves also reduce forceson the steering linkage. These valves are auto-matically set to axle stops after installation invehicle at first full right and left turn.

The procedure for air bleeding follows in thismanual. Replacement of damaged automaticbleed plugs, and manual bleed screws isdescribed in a later section.

General Design

Integral Power Steering

TAS power steering gear is the latest design inthe TRW Commercial Steering Division familyof integral hydraulic power steering gears.Integral hydraulic power steering means thatthe gear contains a manual steering mecha-nism, a hydraulic control valve, and a hydraulicpower cylinder, all in a single, compact pack-age.

Rotary Control Valve

The rotary control valve combines simplicity ofconstruction with desirable performance char-acteristics. The speed at which the driver canturn the steering wheel with power assist isdependent upon the pump flow (measured ingallons per minute) directed to a cylinder cavi-ty. The control valve controls flow through thesteering gear.

The pressure (measured in pounds per squareinch) required for the gear to steer the vehicleis created by the power steering pump to over-come resistance at the steered wheels. Thecontrol valve senses these requirements and


5-6

directs fluid to the appropriate cylinder cavity inthe steering gear at the proper flow rate andpressure.

Pressure Means Work, Flow MeansSpeed

The higher pressure a steering gear can with-stand, the more work it can perform. The maxi-mum operating pressure gears is 2,175 psimaximum flow rate is 8 gal/min.

The TAS series gears can steer a vehicle with-in its front end weight rating through a turn atlow speed and engine idle. As the driver turnsthe steering wheel faster or slower, more orless fluid will be required by the gear.

Approved Hydraulic Fluids

Automatic Transmission Fluid Dexron IIMobil ATF 210Automatic Transmission Fluid Type "E" or “F”Mobil Super 10W-40 Motor OilChevron 10W-40Shell Rotella T30WChevron Custom 10W-40 Motor OilShell Rotella T SAE 30Chevron Torque 5 FluidTexaco 10W-40Exxon Nuto H32 Hydraulic FluidTexaco TL-1833 Power Steering FluidFleetrite PSF (Can #990625C2)Union 10W-40Ford Spec. M2C138CJUnion 15W-40Mack EO-K2 Engine OilUnocal Guardol 15W-40 Motor Oil

The steering system should be kept filled withone of the above fluids.

WARNING

Completely flush the steering system with oneof the recommended fluids above only. Do notmix oil types. Any mixture or any unapprovedoil could lead to seal deterioration and leaks. Aleak could ultimately cause the loss of fluid,which could result in a loss of power steeringassist.

Initial TAS Installation

• Bolt gear to frame, torque to vehicle manufac-turer's recommendation.

• Connect return line to steering gear returnport.

• Connect hydraulic line from pump to pressureport in steering gear unit.

• Connect steering column to input shaft, torquepinch bolt to recommendation.

• Install pitman arm on output shaft, torque boltto recommendation.

Initial Poppet Setting

For this procedure to work correctly, you musthave: A new gear received from TRW or yourvehicle manufacturer's aftermarket system, or aused gear on which poppet seats have beenreplaced or reset during gear disassembly pro-cedures. ALSO: Fixed stop screw installed inhousing, or poppet adjusting screw installed sothat it duplicates fixed stop screw length.

CAUTION

The axle stops and all steering linkage must beset according to vehicle manufacturer's specifi-cations, and the pitman arm must be correctlyaligned on the sector shaft for poppets to be setcorrectly.


5-7

Full turn in one direction

1. With the engine at idle and the vehicleunloaded, turn steering wheel to full travel inone direction until axle stop contact is made.Maximum input torque to be applied during thisprocedure is 40 lb. rim pull on a 20 in. diametersteering wheel.

NOTE: If you encounter excess rim pull effort,allow vehicle to roll forward or jack up the vehi-cle at the front axle.

Full turn in other direction

2. Follow the same procedure while turning thesteering wheel in the other direction. The pop-pets are now positioned to trip and reducepressure as the steered wheels approach theaxle stops in either direction.

Maintenance Tips

Never high-pressure wash or steam clean apower steering gear while on or off the vehicle.Doing so could force contaminants inside thegear and cause it to malfunction.

Make sure vehicle wheel cut or clearancesmeet manufacturer's specifications, and makesure pitman arm timing marks are aligned prop-erly to prevent internal bottoming of the steer-ing gear.

Regularly check the fluid and the fluid level inthe power steering reservoir.

Keep tires inflated to correct pressure.

Never use a torch to remove pitman arm.

Investigate and immediately correct the causeof any play, rattle, or shimmy in any part of thesteering system.

Make sure the steering column is aligned prop-erly.

Encourage drivers to report any malfunctions oraccidents that could have damaged steeringcomponents.

Do not attempt to weld any broken steeringcomponent. Replace the component with origi-nal equipment only.

Do not cold straighten, hot straighten, or bendany steering system component.

Always clean off around the reservoir filler capbefore you remove it. Prevent dirt or other for-eign matter from entering the hydraulic system.

Investigate and correct any external leaks, nomatter how minor.

Replace reservoir filters according to require-ments.

If you feel the vehicle is developing excessive-ly high hydraulic fluid temperatures, determinethe cause immediately.

Maintain grease pack behind the output shaftdirt and water seal as a general maintenanceprocedure at least twice a year, in the Springand Fall. Grease fitting is provided in housingtrunnion. Use only NLGI grade 2 or 3 multipur-pose chassis lube, and use only a hand operat-ed grease gun on fitting. Add grease until itbegins to extrude past the sector shaft dirt andwater seal.


5-8

Filling and Air Bleeding theSystem

TOOLS REQUIRED - 5/16” SocketLbf•in. Torque wrench

MATERIALS REQUIRED - Hydraulic fluid

CAUTION

Make sure poppets are set correctly beforebeginning this procedure.

Run engine for 10 seconds, turn off and fillreservoir

1. Fill the reservoir nearly full. Do not steer.Start and run the engine for 10 seconds, thenshut it off. Check and refill the reservoir. Repeatat least three times, checking the reservoireach time.

CAUTION

Do not allow the fluid level to drop significantlyor run out of the reservoir. This may induce airinto the system.

Run engine for 2 minutes, turn off and fillreservoir

2. Start the engine and let it idle for 2 minutes.Do not steer. Shut off the engine and check thefluid level in the reservoir. Refill as required.

Steer vehicle

3. Start the engine again. Steer the vehiclefrom full left to full right several times. Add fluid,as necessary, to the full line on the dip stick.

Automatic bleed systems should now be freefrom trapped air. Manual bleed systems contin-ue with step 4.

Allow air to bleed out from bleed screw

4. With engine idling, steer from full left turn tofull right turn several times. Stop steering andloosen the manual bleed screw about one turn.Allow air and aerated fluid to "bleed out" untilonly clear fluid is seen. Close the bleed screw,refill the reservoir if required.

Repeat step 4 three to four times until all the airis discharged. Torque manual bleed screw to30 Ibf~in.

CAUTION

Do not turn steering wheel with bleed screwloosened.


5-9

Disconnect return line

1. Disconnect return line from the steering gear and plug theline. Also cap the return port of the gear with a high pressurefitting.

Disconnect column

2. Remove the steering column from the gear input shaft.

Remove dirt & water seal

3. Remove the dirt and water seal from the steering gear.

Remove retaining ring

4. Wipe out the grease and the~ remove the spiral retainingring. Use a screwdriver inserted into the notch formed in theend of the ring. Be careful not to scratch the bore with thescrewdriver.

Input Shaft Seal Replacement

TOOLS REQUIRED - Hammer, J37073,Screwdriver

MATERIALS REQUIRED - Clean cloth, Drip pan,High pressure fitting, Hydraulic fluid, Plug, Shoptowel.

This procedure uses the vehicle’s powersteering pump to force out the input shaftseal. To use this procedure, the power steer-ing pump should have a minimum of 1,500PSI available.


5-10

Replace column

5. Slip the steering column back onto the input shaft with thepinch bolt installed, but no tightened.

Wrap exposed area

6. Tie or wrap a shop towel around the input shaft area andplace a drip pan under the vehicle to catch oil.

Fill reservoir

7. Add fluid as necessary to the full line on the dipstick. Donot mix fluid types.

WARNING - Any mixture of fluid types, or useof any unapproved fluid could lead to seal deterioration andleaks. A leak could ultimately cause the loss of fluid, whichcould result in a loss of power steering assist.

Force out seal

8. With the vehicle in neutral, momentarily turn the starter(quickly turn off the engine if it starts).

Remove input shaft seal

9. Remove the shop towel. Disconnect the steering column,and remove the input shaft seal.

Input Shaft Seal Replacement (Cont.)


5-11

Inspect seal area

10. the seal area of the valve housing for any seal frag-ments. Remove any that are found.

Inspect old seal

11. Check the seal for heat damage. If the seal is stiff andbrittle, and not pliable like the new seal, it is probably heatdamaged. Determine and fix the cause of excessive heat inthe vehicle.

Install new seal

12. Put clean grease (Mobil Temp 1 or 2 or equivalent) on theinside dia. of the new input shaft seal, and place it over theinput shaft. With the small dia. of tool J37073 against theseal, tap the tool until the tool shoulder is square against thevalve housing. Remove any seal material that may havesheared off in the seal bore or retaining ring groove.

CAUTION: Do not use a socket to install sealbecause you will not be able to control seal installation depth,possibly causing a leak.

Install retaining ring

13. Insert new retaining ring into the groove.

Install dirt & water seal

14. Pack the end of the sing bore around the input shaft withclean, high temperature industrial grease (Mobile Temp 1 or2 or equivalent). Apply more of the grease to a new dirt &water seal and install it over the input shaft. Seat it in thegroove behind the serrations and against the valve housing.



5-12

Reconnect column

15. Reconnect the steering column to the input shaft andtighten the pinch bolt to torque level specified.

Reconnect return line

16. Reconnect the return line to the steering gear return port.

Air bleed system

17. Air bleed the system using the air bleeding procedure inthis section.



5-13

Center the sector shaft

1. With the engine off, rotate the steering wheel (input shaft)until the timing mark on the sector shaft lines up with themark on the housing. The line on the sector shaft should beat a 90˚ angle from the input shaft. The sector shaft is nowon its “center of travel”.

Remove the drag link

2. Remove the drag link from the pitman arm.

CAUTION: To avoid resetting the poppets, donot rotate the input shaft more than 1-1/2 turns from the “cen-ter of travel” position while the drag link is disconnected.

Check for sector shaft lash

3. From the “center of travel” position, grasp the pitman armand gently try to rotate it. If looseness or lash is felt at thispoint, the sector shaft is out of adjustment.

Loosen jam nut

4. Loosen the jam nut.

Sector Shaft Adjustment

TOOLS REQUIRED - Screwdriver, 3/4” Socket,3/4” Open end wrench

This adjustment can only be completed on thevehicle if the adjusting screw jam nut is acces-sible. This nut is located on the side cover.

Photos in this section were taken on a mockframe rail for clarity.


5-14

Position adjusting screw

5. If no lash was detected in step 3, turn the shaft adjustingscrew counterclockwise until you feel lash at the output shaft.

Adjust shaft

6. Slowly turn the shaft adjusting screw clockwise until youfeel no lash at the output shaft without using more than 10lbf•ft of torque. From this position, turn the screw clockwise1/8 to 3/16 of a turn more. Hold the adjusting screw in place,and tighten the jam nut. Final torque 43 lbf•ft.

Recheck for lash

7. Turn the steering wheel 1/4 turn each side of center, thenback to center and recheck the pitman arm for lash. Youshould feel no lash; if there is lash, repeat steps 4, 6 and 7.

Connect drag link

8. Reconnect the drag link to the pitman arm.

CAUTION: Maintain grease in the sector shaftbearing through the grease fitting in the housing using only ahand operated grease gun. Add grease until it begins toextrude past the dirt and water seal. Do not use a powergrease gun because it will supply grease too fast; this couldadversely affect the high pressure seal and contaminate thehydraulic fluid.

Sector Shaft Adjustment (Cont.)


Set axles stops, warm-up system

1. Set the axle stops to provide a 5/8” minimum clearance ofthe tire with any chassis component.

Start the engine and allow the vehicle to idle for 5-10 minutesto warm the hydraulic fluid. Shut off the engine.

Assemble adjusting screw into nut

2. If a new poppet adjusting screw and nut are being used,turn the screw into the non-sealing end of the jam nut untilthe drive end of screw is flush with the nut.

Your steering gear will have either fixed stop bolt or anadjusting screw. If the adjusting screw is already part of thesteering gear, back the nut off of the adjusting screw until it isflush with the end of the adjusting screw.

Remove poppet stop bolt

3. Make sure the engine is off and the road wheels are instraight ahead position. Remove and discard the poppetfixed stop bolt (if equipped) and washer (if equipped) from thelower end of the housing.

If the unit has a poppet adjusting screw and sealing nut thatneed to be replaced, remove and discard them.

Turn adjusting screw assembly into housing

4. Turn the adjusting screw and sealing nut assembly, with-out rotating the nut on the screw, into the housing until the nutis firmly against the housing using a 7/32” allen wrench.Tighten the sealing nut against the housing.

CAUTION: If the drive end of the screw isbelow the face of the nut, the poppet seat flange will breakduring step 7d.

Poppet Readjustment

TOOLS REQUIRED - 7/32” allen wrench, 5/8”open end wrench, 3/4” open end wrench, 3/4”socket, lbf•lb torque wrench.

MATERIALS REQUIRED - hydraulic fluid, jack

This resetting procedure will work in mostcases with at least 1-3/4” hand-wheel-turnsfrom each side of center. If you’re making alarge reduction cut and this procedure doesnot work, you may have to replace or internal-ly reset the poppets.

5-15


Refill reservoir

5. Refill the system reservoir with approved hydraulic fluid.

CAUTION: Do not mix fluid types. Mixing oftransmission fluid, motor oil, or other hydraulic fluids willcause seals to deteriorate faster.

Jack up vehicle

6. Place a jack under the center of the front axle and jack upthe front end of the vehicle so the steer axle tires are off theground.

Push upper poppet out to prepare it for setting

7. a. Start the engine and let it run at idle speed.

b. Note which output shaft timing mark is nearest the hous-ing piston bore.

c. Turn the steering wheel in the direction that makes thistiming mark move toward the adjusting screw just installed inthis direction until axle stop contact is made.

d. Pull hard on the steering wheel (put up to 40 lb rim pull ona 20” dia. steering wheel) after the axle stop is contacted.

Set upper poppet

8. a. Turn the steering wheel in the opposite direction (endof timing mark away from adjusting screw)until the other axlestop is contacted.

b. Pull hard on the steering wheel (put up to 40 lb rim pull ona 20” dia. steering wheel).

c. Release the steering wheel and shut off the engine.

Back out adjusting screw

9. Loosen the sealing nut and back out the adjusting screwuntil 1” is past the nut. Tighten the sealing nut against thehousing.

CAUTION: Do not hold the steering wheel atfull turn for more than 10 seconds at a time; the heat build-upat pump relief pressure may damage components.

5-16


5-17

Set lower poppet

10. a. Start the engine and let run at idle speedb. Turn the steering wheel in the original direction (end oftiming mark toward adjusting screw), until axle stop contactis made.

b. Hold the steering wheel in this position (with up to 40 lbrim pull) for 10 seconds, then release. Repeat this holdand release process as many times as necessary whilecompleting step 11l.

Position adjusting screw

11. a. With steering wheel held tightly at full turn loosenthe jam nut and hold it in place with a wrench.

b. Turn the adjusting screw in (clockwise) using finger-pressure only (don’t use a ratchet), until the allen wrenchstops. Do not attempt to turn it in further. Pause the turn-ing-in process each time the driver releases the steeringwheel; continue turning only while the wheel is held at fullturn.

c. Back off the adjusting screw 3-1/4 turns and tighten thesealing nut. Torque sealing nut to 35 lb•ft.

The procedure is complete

12. The poppets have now been completely reset. Lowerthe vehicle. Check the reservoir and fill if required.

WARNING: The length of the adjusting screwbeyond the nut must be no more than 1-1/16” for properthread engagement.

NOTE: The length of adjusting screw beyond the sealingnut may be different for each vehicle.

Poppet Readjustment (Cont.)


5-18

TAS Steering DesignFeatures

1. Rotary Valve - This device provides respon-sive steering control.

2. Poppets - These unloading valves are auto-matically set to furnish power steering pumpprotection and reduce pressure to unload steer-ing linkage at vehicle axle stop settings.

3. Recirculating Balls - Combine highmechanical efficiency with smooth operation.

4. Dirt & Water Seals - Lip-type seals on bothinput and output shafts.

5. Torsion Bar - Provides positive valve cen-tering with definitive “feel of the road”.


FRONT END ALIGNMENT

The following notice applies to one or moresteps in the assembly procedure of component,this portion of the manual as indicated at appro-priate locations by the terminology:

NOTICE: Front end alignment fasteners areimportant attaching parts in that they couldaffect the performance of vital parts and sys-tems, and/or could result in major repairexpense. They must be replaced with one ofthe same part number or with an equivalent partif replace becomes necessary. Do not use areplacement part of lesser quality or substitutedesign. Torque values must be used as speci-fied during reassembly to assure proper reten-tion of all parts.

Description

Alignment is the proper positioning or state ofadjustment of parts in relation to each other.

Proper alignment of front wheels must be main-tained to insure efficient steering and satisfac-tory tire life. The most important factors of frontend alignment are wheel toe-in, wheel camber,and axle caster, King-pin inclination isdesigned into the axle end. Front end align-ment should be checked at regular intervals,and particularly after the front axle has beensubjected to heavy impacts such as a collision.Before checking alignment. Insure that frontwheel bearings are properly adjusted. T h ewheel bearings will affect the instrument read-ings when checking the wheel toe-in, wheelcamber, and axle caster.

When checking the alignment, the instructionsoutlined in this section should be followed care-fully, as well as instructions covering relatedunits such as brakes, and wheels and tires,which are given in other sections of this manu-al. The front end alignment chart (Figure 9-5)indicates the points at which the alignmentdimensions are taken.

Figure 5-5

5-19


Definition of Terms - TOE-IN - The dis-tance between the front wheels is less at thefront that at the rear of the axle (E and F, Figure9-5)

Toe-InThe distance between the front wheels is lessat the front than at the rear of the axle (E andF, Figure 5-5)

Camber

Camber (A, Figure 5-5) is the amount indegrees that front wheels are tilted outward atthe top from vertical position (C, Figure 5-5).Camber offsets wheel deflection, due to wear offront axle parts, and prevents a reverse or neg-ative camber condition. A reverse or negativeis an inward inclination of wheels at the top.

If camber is extreme unequal between thewheels, improper steering and excessive tirewear will result.

Caster Adjustment

Caster is the fore and aft tilt (toward front or rearof vehicle) of the steering kingpin as viewedfrom the side of the vehicle.

“Positive” caster is the tilt of the top of the king-pin toward the rear of the vehicle.

“Negative” caster is the tilt of the top of the king-pin toward the front of the vehicle.

A caster angle more positive than specifiedmay result in excessive steering effort and/orshimmy. An angle less positive may result invehicle wander or poor steering return to cen-ter. Caster angle is determined by the installedposition of the steer axle.

Caster is adjusted by adding or removing taperwedges between the springs and axle beammounting pad.

The caster angle is generally more positive withpower steering, since the power-assist over-comes excessive steering effort. This enablesthe vehicle to exhibit maximum straight aheadsteering stability (common range for powersteering units is +1° to +2°).

King Pin Inclination

King pin inclination is designed into the axleend and is the amount that the top of the kingpin is inclined toward the center of vehicle.King pins are inclined (D, Figure 5-5) to assistfront return to center after a turn is executed.

5-20


Frame angle

The caster, camber, and toe-in dimensions arefor vehicle at design load (with frame level). Ifframe is not level on alignment equipment, theframe angle must be considered. This is espe-cially important when making caster anglecheck to obtain a true setting.

On-Vehicle Service

Inspection

Before checking the front end alignment, thefollowing front end inspection should always bemade:

1. Check the tires for proper inflation pressure.Note that the rim-to-floor need be the same ateach wheel.

2. Check the wheel installation and run-out.

3. Check the wheel bearing adjustment.

4. Check the steering tie rod and drag link endsfor looseness.

5. Check the king pins for looseness.

Checking and Correcting Toe-In

Incorrect toe-in results in excessive tire wearcaused by slide slippage and also unstablesteering with a tendency to wander. Toe-inmay be measured from the center of the tiretreads or from the inside of the tires. Measureat both the front and rear of the axle (E and F,Figure 5-5). Note that the toe-in measurementsmust be made at the horizontal axis of thewheel.

Toe Setting1. Use a work bay with a level floor.2. Drive the vehicle into bay slowly and straight

ahead. Try to roll to a stop without the use of

brakes.3. Chock the rear wheels. Place a 5" (127 mm)

long piece of masking tape parallel to thecenter tread rib on the rear of both tires, halfway up the tire height.

5. Position a trammel bar behind the front tires.The pointers should be raised/lowered untilthey are at the hub’s centerline height.

6. With the trammel bar pointers at the hub’scenterline height, place the pointers at theoutside edges of the masking tape andsecure the pointer set screws.

7. Mark the location of one of the pointers witha simple horizontal mark on the maskingtape.

8. Remove the trammel bars from behind thewheels.

9. Roll the truck forward until the mark on thetape travels 180-degrees.

10. Position the trammel bar at the front of thetires. Position the pointer to the edge of thetape on the side that has the horizontalmark. The pointer and the mark should be atthe same height.

11. Measure the toe between the pointer andthe edge of the tape on the opposite tire toget the total toe measurement.

Note: Toe-in specification is 1/16” (1.587 mm)for unloaded vehicles. This applies to a tractor(less trailer) or straight truck with no load.

12. If the toe measurement is incorrect, loosenthe tube clamp and bolt on the end of eachof the cross tubes. Turn the cross tubes untilthe specified distance is reached.

13. Make sure the threaded portion of the tieends are inserted completely and are visiblein the complete cross tube slot. Tighten thebolt and nut on the ends of the cross tube tothe specified torque.

14. Check the toe settings again.

5-21


Checking and Correcting Camber

Camber variations may be caused by wear atwheel bearings and steering knuckle bushings,or by a bent steering knuckle or axle center.Camber specifications are listed at the end ofthis section.

Before checking the camber, check wear at theking pins as follows:

Raise the front of the vehicle, pull bottom of thewheel outward and take a camber reading.Then pull the top of the wheel outward and takea camber reading. Then pull the top of thewheel outward and take a camber reading. Ifthe readings vary more than 15 minutes (1/4”)make the following adjustments:

1. Adjust the wheel bearings as directed inunder front axle section, then take the camberreadings. If the readings still vary over 15 min-utes, check and replace if necessary, the steer-ing knuckle bushings and king pins.

2. Check the wheel run-out as instructed inwheel tire runout check. If the run-out is exces-sive, replace the wheel.

3. Place the vehicle on a level surface with thenormal weight of the vehicle on the wheels,then take the final camber reading. If a cambergauge is not available, the readings can betaken as shown in Figure 5-5. Place the squareas shown and measure distances A and B. Bshould EXCEED A. Camber dimensions of theright wheel should not vary over 3/32” fromcamber dimensions of the left wheel. If the finalcamber reading is incorrect, either the steeringknuckle or the axle center is bent.

4. To determine which part is bent, check theking pin inclination (D, Figure 5-5). Camberplug king pin inclination is the included angle ofsteering knuckle. If the included angle variesmore than 30 minutes (1/2”), the knuckle isbent and should be replaced. Excessive posi-

tive camber causes wear at the inner shoulder.Incorrect camber setting will affect steeringeffort.

Checking and Correcting Caster

Caster dimensions are for a vehicle carrying itsdesign load. Design load is the load equal tothe capacity of the vehicle’s suspension,whereby the frame in most cases would belevel. If an alignment check is to be made withthe frame NOT LEVEL, the frame angle mustbe determined and added to the caster angle toobtain a true caster reading. To determineframe angle proceed as follows:

1. Position vehicle on a smooth level surface.

2. Using a bubble protractor or inclinometer,measure the frame angle. Frame angle is thedegree of tilt in the frame from the level posi-tion.

3. Determine whether the frame angle is up inrear or down in rear.

4. Determine the caster angle for the left wheelnot.

5. To determine an actual (corrected) casterreading with various frame angles and casterreadings, one of the following rules applies:

a. A DOWN IN REAR frame angle mustbe SUBTRACTED from a POSITIVE casterreading.

b. AN UP IN REAR frame angle mustbe ADDED to a POSITIVE caster reading.

c. A DOWN IN REAR frame angle mustbe ADDED to a NEGATIVE caster reading.

d. An UP IN REAR frame angle must beSUBTRACTED from a NEGATIVE caster read-ing.

5-22


6. Repeat steps 2 through 5 for the right wheel.

7. If the caster is not within specifications, cast-er can be corrected by selecting proper castershims between the axle and the spring.

Turning Angle (Stop ScrewAdjustment)

Turning angle, or toe-out on turns is determinedby the angle of the steering arms. Regardlessof maximum turning angles, adjustment of stopscrew must provide 5/8” minimum clearance ofthe tire with any chassis component. If frontwheel stop screw adjustments are made, thepoppet valves in the steering gear must also beadjusted.

Adjustment (Figure 5-6)

1. Loosen the jam nut and turn in the right stopscrew so that screw will not contact it’s stopwhen wheels are turning to the right.

NOTE: Turn wheel to a position that 5/8” trueclearance is maintined.

2. With the wheels turned to the extremeright,then turn out the stop screw until it con-tacts firmly against it’s stop. Check the positionof the tire. If the tire has less than 5/8” clear-ance from any chassis obstruction, adjustscrew to obtain clearance.

3. Repeat steps 1 & 2 on left side.

4. When installing oversized tires, recheck theturning clearance and stop screw setting.

Wheel and Tire Runout Check

Wheels that are thought to be distorted may bechecked as follows:

1. Raise the axle at the side to be checked andsupport it.

2. Make a tool for checking runout.

a. Secure a block of wood 6 X 6 X 14inches or material with a suitable base so it willremain in position.

b. Secure a thin piece of wood or a suit-able material 10 inches long (ruler or yardstick).

c. Fasten the thin wood to the block to aheight in relation to the rim surfaces.

d. Tighten the screw just so the pointerwill hold its position when adjusted.

3. Position the pointer at the crown of the rim.

4. Slowly turn the wheel and move the pointertoward the wheel until it touches the wheel atthe nearest point.

5. Continue to turn the wheel and check theamount of lateral runout (the amount of wheelside wobble). This should not exceed 3/32”.

6. Place the point of the marker at the inside ofthe wheel.

Figure 5-6

5-23


7. Follow the previous procedure to check theradial runout (out of round condition). Thisshould not exceed 3/32”.

a. If wheel is distorted beyond thesemeasurements, replace the wheel.

Hub Check

If it is doubtful whether it is the wheel of the hubthat is distorted, check the hub as follows:

1. Replace the existing wheel with a wheelknown to be true.

2. Turn the wheel and make the previous tests.a. If the tests are within the limits, the

tire is good, but the wheel is sprung.

5-24


Disassembly, Overhaul, andAssembly

Steering Knuckle Disassembly

Preparation1. Set parking brake and block drive wheels to

prevent vehicle movement.2. Raise vehicle until steer axle tires are off the

ground. Support raised vehicle with safetystands.

WARNING

Never work under a vehicle supported by onlya jack. Always use safety stands.

Procedure

1. Loosen the slack adjuster to return brakeshoes to the released position and cleardrum.

2. Remove hub cap, cotter pin, nut, washer,and outer bearing cone assembly.

3. Remove wheel and hub assembly.4. Disconnect air or hydraulic line from the

brake assembly.

Note: Plug or cap line to prevent brake systemcontamination.

5. Remove brake assembly.6. Remove cotter pin and slotted nut.

7. Disconnect tie rod end from tie rod arm usinga suitable tool such as a pickle fork.

Note: If boot is torn during removal, tie rod endmust be replaced.

CAUTION

Do not use heat on any axle parts or fasteners.

8. Disconnect drag link from steering arm byremoving cotter pin and slotted nut.

9. Remove top and bottom knuckle caps.10. Single draw key. Remove nut from draw

key, then drive key out using a brass ham-mer and drift.

5-25

5-26

FRONT AXLE & STEERING

11. Dual draw keys. Remove both draw keynuts. Then drive key out using a brass ham-mer and drift.

12. Drive kingpin out with a brass hammer anddrift.

13. Remove steering knuckle from axle beam.

WARNING

Never strike hardened metal parts with a steelhammer or tool.

Cleaning

After disassembly and before attemptinginspection, clean parts as follows:

1. Steel parts with ground or polishedsurfaces.

• Wash in suitable cleaning solvent.• Rinse thoroughly to remove cleaning

solution.• Dry parts with clean rags.2. Clean castings, forgings and other

rough-surface parts.• Wire brush or steam-clean areas that

are susceptible to accumulation ofmud, road dirt, salt.

WARNING

Gasoline is not an acceptable cleaning solventbecause of its extreme combustibility. It isunsafe in the workshop environment.

Kingpin Bushing and SealReplacement Removal

1. Remove grease seals from knuckle armsusing suitable tool.

Remove Kingpin Bushings

2. Drive bushings out of knuckles using suit-able piloted drift.

3. Remove all foreign material from kingpinbore of Steering knuckle and axle beambore.

4. Wire brush machined surfaces taking carenot to damage them. Clean kingpin bores.


WARNING

During removal and installation procedures,never use steel hammer or tool to strike hard-ened metal parts.

Bushing Installation

5. Lightly lubricate outside diameter of bush-ings to ease installation.

6. Hand start bushing in bore.

7. Drive bushings in until they are located asshown.

• Use same method to install both upper andlower bushings.

Note: Some Dana Spicer kingpin bushingsrequire reaming after installation. Read theinstruction sheet included with the service kit orbushings BEFORE beginning installation. Fordimensions of bushings requiring reaming, referto the Kingpin Bushing Specifications chartshown in the Appendix.

8. Ream bushingsto proper sizeusing appropri-ate Kent-Mooretool (or equiva-lent).

9. Install new seal,using suitablepilot drift or sim-ilar device thatwill not damage seal as it is installed.

CAUTION

When installing grease seal, be sure lip is point-ing toward center of knuckle. This is essentialfor correct seal operation.

5-27


FRONT SUSPENSION

INTRODUCTION

The front suspension consists of two multi-leave semi-elliptical springs, rubber bumpers,shackles and related hardware. The followingparagraphs outline the complete removal andinstallation procedures for the springs andshackles.

Perform only those steps necessary to effectthe desired repairs.

Removal

1. Park machine on level surface, set parkingbrake and block rear wheels to prevent move-ment.

WARNING

Do not work under vehicle supported only byjacks. Install jack stands and/or wooden blocksto prevent vehicle from falling.

2. Jack up front of vehicle until wheels clearground and install jack stands or wood blocksto support weight of vehicle.

3. Remove front wheels.

4. If both springs are to be replaced, performaxle removal procedures, then go to step 8. Ifonly one spring is to be serviced, go to step 5.

5. Place jack under axle under spring (13) thatis to be serviced.

6. Refer to figure 5-12 and remove locknuts(20) and bolts (11) to release axle from spring(13).

7. Lower axle away from spring (13).

8. Remove bolts and lockwashers (8 and 9)then drive out spring pins (7) to release spring(13).

9. Remove bolt and lockwasher (8 and 9) thendrive out shackle pin (7) to release shackle (3)and bushing (6).

10. Remove locknuts and washers (4 and 5) toremove bumpers (17).

Inspection

1. Check springs (6) for cracked or brokenleaves. Check end bushings (14 and 18) fordeterioration.

Figure 5-12

1. SELF LOCKING NUT 11. BOLT2. AXLE BUMPER 12. MOUNTING PLATE3. SHACKLE SPRING 13. SPRING4. FLAT WASHER 14. FLAT WASHER5. BOLT 15. SHOCK ABSORBER BOLT6. SPRING BUSHING 16. SHOCK ABSORBER7. SPRING PIN 17. WASHER8. LOCK WASHER 18. NUT9. SPECIAL BOLT 19. SHOCK ABSORBER BRKT.10. GREASE FITTING 20. SELF LOCKING NUT

5-28

CAPACITY REAR AXLE & DURA RIDE

TOPIC 6 – REAR AXLE & DURA-RIDE SUSPENSION

Terminal Objective:

Upon completion of this unit, the student will be knowledgeable in the identification, pro-cedures and repairs found on the rear axle & dura-ride suspension found on Capacityspotters.


• Identify the rear axle specifications and identify it as an assembly or in comp-nents form.

• Understand basic operation, front bearings, air springs, height adjustment andshock inspection.

• Understand basic operation, procedures for air dryer operation and its compo-nents

6-1


6-2

Drive Axle

The following procedures outline the removaland installation of the drive axle from a spottingtractor equipped with the optional Dura Riderear suspension system. Refer to the figures asindicated for location and identification of partswhile performing these procedures.

Removal

1. Park tractor on level surface and blockFRONT wheels to prevent movement.

2. Perform the following procedures to ''cage"the parking brake springs.

3. CAGING BRAKE CHAMBER

a. Refer to Figure 7-6 (Section 7) andremove release stud (17) from carrying pocketin the housing.

b. Remove access plug (13) then insertrelease stud (17) through hole in housing andthrough spring pressure plate (10).

c. Turn release stud (17) 1/4 turn toengage tangs on release stud with slots inpressure plate (10).

d. Install release stud nut (20) on releasestud (17) and tighten nut until spring (11) iscompletely caged.


6-3

11. Refer to figure 9-9 and mark location of link-age connector as shown then, loosen clampand slide connector up off linkage rod.

12. Attach a suitable hoist to the rear of thevehicle frame then hoist the frame high enoughto allow the axle to be removed.

13. Install jack stands to support raised vehicleframe.

14. Remove drive shaft.

15. Remove bolt (21, figure 9-8), lockwasher(22) and hydraulic hose support bracket (23).

16. Remove locknuts, washers and bolts (17,18 and 19) to release air springs (2) and mount-ing plates (20).

17. Attach suitable hoist to raised end of boomand exert a lifting force that will support weightof boom and Dura-Ride "A" frame (31).

4. Refer to Figure 9-7 and remove cotter pin (1)and clevis pin (2) to disconnect brake chamberclevis (3) from slack adjuster (4).

5. Apply parking brake then release air brakesystem pressure to zero pressure bydepressing and releasing brake pedal approxi-mately 30 times.

6. Tag, disconnect and plug the air lines (5 and6) from both brake chambers (7).

7. Raise boom to the top of its travel for access,then install supports to hold boom elevated.

8. Refer to figure 9-8 and disconnect air hose(1) from each air spring (2) then remove fitting(12), top locknuts (3) and washers (4).

9. Remove locknuts (5 and 7), bolts (8) andwashers (6 and 9) to release shock absorbers(10).

10. Remove locknut (11), locknuts (13), bolts(14) and washers (15) to release track rod (16).

Figure 9-7


6-4

Disassembly and Repair

1. Refer to the axle manufacturer's service andrepair information supplied with the Tr a i l e rJockey for disassembly and repair proceduresfor the internal components of the drive axle.

Installation

1. Position drive axle (30, Figure 9-8) on "A"frame (31) then install brackets (29), bolts (27),washers (28 and 24) and locknuts (26). Referto torque chart in this manual for correct torquevalues.

2. Once locknuts (26) are torqued, install jamnuts (25).

3. Assemble air springs (2) to mounting plates(20) using washers (33) and locknuts (32) then,install mounting plates (20) on brackets (29)using bolts (19), washers (18) and locknuts(17).

4. Use hoist to raise boom, "A" frame and axlethen install rear wheels.

5. Raise vehicle frame, remove jack stands orwooden blocks then, carefully align the studson top of the air springs (2) with mounting holesin frame. SLOWLY lower vehicle frame onto airsprings (2). Install washers (4), locknuts (3) andfitting (12).

6. Connect air hoses (1) to air springs (2).

7. Install track rod (16) using bolts (14), wash-ers (15), locknuts (13) and locknut (11).

8. Install shock absorbers (10) using bolt (8),washers (9 and 6) and locknuts (7 and 5).Tighten locknuts (5 and 7) until washers (6 and9) are 1-3/4 inches apart.

9. Install air hose support bracket (23) usingbolt and lockwasher (21 and 22).

WARNING

Be certain Dura Ride "A" frame (31) is support-ed before removing axle mount locknuts andbolts.

18. Remove jam nuts (25), locknuts (26), wash-ers (24), bolts (27), washers (28) and brackets(29).

19. Use hoist supporting boom to lower "A"frame (31) then roll axle (30) out from undervehicle.

20. Lower boom until "A" frame (31) rests onthe floor.

21. Use fork Lift to transport axle (30) to pre-pared work area.

Inspection

1. Check all threaded components for damagedor stripped threads. Repair light damage withthread chasers. Replace parts found unservice-able.

2. Check air springs for cracks, tears or othersigns of damage or wear. Replace worn airsprings.

3. Check operation of shock absorbers andcheck for leaks. Replace worn or leakingshocks.

4. Check bracket (29) welds for cracks. Havecracks welded.

5. Check condition of track rod (16) bushingsfor deterioration. Replace worn bushings.

6. While the axle is removed, the Dura-Ride "A"frame bearing should be checked for wear.Refer to bearing inspection procedures.


6-5

Figure 9-8


6-6

16. Reinstall access plug (13).

17. Refer to Figure 9-9 and slide connectordown onto rod to mark made during disassem-bly. Tighten clamp to secure connector.

18. Refer to the LUBRICATION CHART in theand service drive axle with specified lubricant.

19. Perform brake adjustment.

20. Perform ride height adjustment proceduresoutlined in this manual.

21. Check all air hose connections for leaksusing soapy water solution.

10. Perform drive shaft installation procedures.

11. Refer to Figure 9-7 and connect air lines (5and 6) to brake chambers (7).

12. Start engine and allow air pressure to buildto normal operating level, then release parkingbrake.

13. Connect clevis (3) to slack adjuster (4) withclevis pin (2) and cotter pin (1).

14. Uncage brake chamber by loosening nutuntil spring is fully released.

15. Remove release stud assembly (17) andreturn it to its storage position on the housing.

9-9


Shock Absorbers

Shock absorbers are nonrepairable.Maintenance requirements involve replace-ment of the rubber mounting grommets, andtightening all shock absorber pin nuts at regularintervals. If a shock absorber becomes inoper-ative, the complete unit must be replaced.

Shock Absorber Inspection

Shock absorbers are a sealed assembly andmust be replaced if faulty.

1. Disconnect both lower shock mountings andpull down on the shock until it is fully extended.

2. Inspect for leaks in the piston rod seal area.Shock fluid is a thin hydraulic fluid, dark brownin color with a characteristic odor. A slight traceof fluid seepage is permissible, as the seal isdesigned to seep a slight amount of fluid to pro-vide for piston rod lubrication.

If a great deal of oil is present, be certain thatthe oil does not originate from some othersource (oil spray from engine, air compressor,etc.) before presuming the shock to be leaking.

3. Grip the lower end of the shock securely andstroke up (compression stroke) and down(rebound stroke) several times. Reboundresistance (extending the shock) should begreater than the compression resistance. If indoubt, compare resistance or suspected shockwith a new one. Resistance should be smoothand constant for each stroking rate. Replaceshock if any binding or unusual noises arepresent.

4. Extend shock to the limit of its travel andinspect for a bent damper rod. Replace if nec-essary.

5. Compare the compression and reboundresistance by stroking both shock absorbers as

in step 3. Replace both units if a definite differ-ence in either compression or rebound resist-ance is felt.

6. Inspect mounting brackets for looseness orwear. Inspect rubber bushings and grommetsfor wear or deterioration.

6-7


6-8

DESCRIPTION

The Dura-Ride suspension system is equippedwith two air springs which are controlled for rideheight by a position sensitive air valve. As moreweight is applied to the fifth wheel, the springscollapse. The valve senses the change in posi-tion and increases spring air pressure to com-pensate for additional load and to restore thevehicle to its original ride height. As the load isdecreased, air is released from the springs tomaintain proper positioning. Spring ride heightshould be approximately 4 1/2.” after air pres-sure has stabilized. Height changes requiredfor load changes are not instantaneous.Stabilization takes 5 - 7 seconds under normalconditions. Ride height is factory set andshould not require adjustment, unless levelingvalve and/or linkage requires replacement.

Service

The Dura-Ride suspension system is furnishedwith five spherical bearings (see Figure 9-1)which allow the suspension to articulate Thebearings should be lubricated weekly. T h ebearings are located at each end of the boomlift cylinders and at the swivel point of the A-frame structural member to which the rear axleis attached. The swivel point grease fitting islocated just above the bearing in the top plateof the A-frame. Remote lube point is providedfor the swivel point bearing. Service the greasefittings at the intervals described in theLubrication Chart.

Inspection

Inspection of the components of the Dura-Ridesystem should be accomplished once a monthor every 200 hours. Inspect the following items:

a. Check all hoses and fittings for leaks,looseness or damage.

b. Check the boom hydraulic cylindersfor leaks.

c. Check the air springs for cracks, leaksand/or damage.

d. Check the connector clamps of theleveling valve linkage for tightness.

e. Check the valves for proper operationby performing ride height check and adjustmentoutlined below:

Ride Height Check

Perform the following steps to determine if theleveling valve and air springs are performingcorrectly.

a. Park Trailer Jockey with no trailer onlevel surface, apply parking brake and shutdown engine.

b. Measure height of air springs asshown in Figure 9-2

c. With no load on tractor, air springsshould be 4-3/8. to 4-5/8" (11.1 1-11.74 cm).

d. Connect Trailer Jockey to loaded trail-er then park in same location, apply parkingbrakes.

e. Measure height of air springs. .

f. With full load, air springs should still be4-3/8 to 4-5/8" (11.11-11.74 cm) tall.

g. If this ride height is not being main-tained, perform the following adjustment proce-dures.


6-9

Figure 9-1


6-10

Figure 9-2


6-11

Ride Height Adjustment

a. Refer to Figure 9-2 and loosen con-nector clamp of top linkage connector.

b. Move top connector up to raise valveactuating lever. This will open leveling valveand allow more air pressure to enter airsprings.

c. When air springs reach correct rideheight (4-3/8" to 4-5/8") slide top connectordown until leveling valve just closes.

d. Tighten top connector clamp.

e. Recheck air spring height both loadedand unloaded.

f. If Trailer Jockey still rides too low,move top connector up slightly. If Trailer Jockeyrides too high, move top connector down.

g. Be certain connector clamp on bottomconnector is tight.

h. Once properly adjusted the air springswill maintain the 4-3/8" to 4-5/8 height, loadedor unloaded.

Pivot Bearing Inspection

a. Park machine on level ground, setparking brake and block wheels to preventmovement.

b. Refer to Figure 9-3 and pry "A" frame(1) to one side and measure distances "A" and"B" between vertical bearing mount plate (2)and each cross tube ear (3 and 4).

c. Subtract the smaller of the two meas-urements from the larger. If the difference ismore than 1/8 perform bearing replacementprocedures. If difference is less than 1/8" thebearing may be reshimmed by performing thefollowing:

(1 ) Place a suitable jack under bearingarea of "A" frame (1) and support weight of "A"frame structure.

Figure 9-3


6-12

(2) Remove cotter pin (5), slotted nut (6),washer (7) and spacer (8).

(3) Drive out pivot pin (9). This willrelease bushings (11).

(4) Install replacement pivot pin (9),bushings (11) and as many shims (10) as will fitbetween the cross tube ears (3 and 4) and thebushings (11).

NOTE

When installing more than one shim, placethem as equally as possible on both sides of"A" frame structure.

(5) Install spacer (8), washer (7) andslotted nut (6). Torque nut to 500 ft-lbs.

(6) Install cotter pin (5).

Rear Suspension

The following paragraphs outline the proce-dures for removal, repair and replacement ofthe components of the Dura-Ride air suspen-sion system. Refer to the figures as indicatedfor location and identification of parts while per-forming these procedures.

Air Springs Replacement

1. Park machine on level surface and set park-ing brake.

2. Raise boom to the limit of its travel for accessto air springs.

3. Bleed all brake system air pressure to zeropressure by depressing and releasing brakepedal approximately 30 times.

4. Refer to Figure 9-4 and disconnect air line(1) from air spring fitting (2).

5. Remove locknuts (3) and washers (4).

6. Use suitable hoist of jacks to raise vehicleframe (5) to clear the stud (6) and tube (7) andfor access to bolts (8) and locknuts (9).

7. Place jack stands and/or wooden blocksunder frame to secure it in the raised position.

8. Remove locknuts (9), washers (10) and bolts(8) to release air spring (12) and mounting plate(11).

9. Remove locknuts and washers (13 and 14)to separate air spring (12) from mounting plate(11).

10. Assemble mounting plate (11 ) to replace-ment air spring (12) with washers and locknuts(14 and 13).

Figure 9-4


6-13

11. Position spring/plate assembly on bracket(15) with, tube (7) to the rear. Secure withbolts, washers and locknuts (8, 10 and 9).

12. Raise frame (5), remove blocks and/or jackstands then, SLOWLY lower frame (5) onto airsprings (12) while watching that tube (7) andstud (6) align with mounting holes.

13. Install washers (4), locknuts (3) and fitting(2) then connect air line (1).

14. Start engine and allow air pressure to buildto normal level. This will automatically inflate airsprings.

15. Check ride height as outlined on page 9.1and perform ride height adjustment if neces-sary (See page 9.4)

16. Check air line connections for leaksusing soapy water solution.

Leveling Valve Replacement

1. Park vehicle on level surface and set parkingbrake.2. Raise boom to the limit of its travel for accessto leveling valve.

3. Bleed all brake system air pressure to zeropressure by depressing and releasing brakepedal approximately 30 times.

4. Refer to Figure 9-5 and pull connector (1)from valve arm (2).

5. Tag, disconnect and plug air lines (3 and 4).

6. Remove locknuts (5), washers (6), bolts (7)and washers (8) to release leveling valve (9).

7. Mark valve arm (2) as shown then loosenbolt (10) to release arm (2). Transfer valve armto replacement leveling valve (9).

Figure 9-5


6-14

8. Transfer fittings (1 1, 12 and 13) to replace-ment leveling valve (9).

9. Position replacement leveling valve (9) onbracket (14) and secure with bolts, washersand locknuts (7, 8, 6 and 5).

10. Connect air lines (3 and 4).

11. Attach connector (1) to valve arm (2).

12. Start engine and allow air pressure to buildto normal operating pressure.

13. Check air line connections for leaks usingsoapy water solution.

14. Perform ride height check and adjustment(see pages 9.1 and 9.4)

A Frame Pivot BearingReplacement

To remove the A-frame pivot bearing, it will benecessary to move the axle/A-frame assemblyback approximately six inches (15 cm). Performthe following procedures to move the axle/A-frame.

1. Park machine on level, smooth surface andblock front wheels to prevent movement.

2. Refer to figure 9-7 and remove cotter pin (1)and clevis pin (2) to disconnect brake chamberclevis (3) from slack adjuster (4).

3. Apply parking brake then release air brakesystem pressure to zero pressure by depress-ing and releasing brake pedal approximately 30times.

4. Raise boom to the limit of its travel for accessto air springs, then install supports to holdboom in elevated position.5. Refer to figure 9-4 and disconnect air hose

(1) from each air spring (2) then remove fitting(12), top locknuts (3) and washers (4).

6. Remove locknuts (5 and 7), bolts (8) andwashers (6 and 9) to release shock absorbers(10).

7. Remove locknut (11), bolts (14) washers (15)and locknuts (13) to release track rod (16).

8. Attach a suitable hoist to the rear of the vehi-cle frame and raise frame until it clears the airsprings.

9. Install jack stands or wooden blocks to sup-port the vehicle frame in its raised position.

10. Disconnect hoist from vehicle frame thenattach hoist to boom. Apply a lifting force suffi-cient to support weight of boom then removebottom boom cylinder bolts and lockwashers (8and 9, Figure 10-11). Once all eight bolts areout, raise boom slightly.

11. Place support under the bearing end of Aframe (10) that will allow the A-frame (10) andaxle (11) to be moved back.

12. Remove cotter pin (3), castellated nut (4),washer (5) and spacer (6).

13. Drive out pivot pin (7). This will releaseshims (8) and bushings (9).

14. Move A-frame/axle assembly (10 and 11)back approximately six inches (15 cm).

15. Remove locknuts (12), bolts (13) and flatwashers (14) to release clamp plates (15) andbearing (16).

16. Position replacement bearing (16) andclamp plates (15) on A-frame (10). Secure withbolts (13), flat washers (14) and locknuts (12).


6-15

1. BOLT2. LOCKWASHER3. COTTER PIN4. CASTELLATED NUT5. WASHER6. SPACER7. PIVOT PIN8. SHIM9. BUSHING

10. A-FRAME11. AXLE12. LOCKNUT13. BOLT14. FLAT WASHER1. CLAMP PLATE16. BEARING17. BOOM CYLINDERS18. COTTER PIN

19. PIN HEAD20. CASTELLATED NUT21. MOUNTING EAR

Figure 9-6


6-16

17. Assemble pin head (19), castellated nut(20) and cotter pin (18) on replacement pivotpin (7).

18. Move A-frame (10) into position betweenmounting ears (21 ) then install replacementbushings (9) and pivot pin assembly (18, 19, 20and 7).

19. Install spacer (6) and washer (5). Lubricatecastellated nut (4) then torque nut to 500 ft.lbs.(678 NM).

20. Pry A-frame to one side then check for agap between bushing (23) and mounting ear(21). Shim to zero clearance by removing nut(4) and pivot pin (22) and adding shims (8)between bushings (23) and ears (21).

21. Once shimming is complete, reinstall spac-er (6), washer (5), nut (4), torque to 500 ft.lbs.(678 NM) and install cotter pins (18).

22. Align the boom cylinders (17) with theirmounting blocks then install bolts and lock-washers (1 and 2).

22. Align the boom cylinders (17) with theirmounting blocks then install bolts and lock-washers (1 and 2).

23. Disconnect hoist from boom then attach itto rear of vehicle frame. Raise vehicle frame toallow removal of jack stands the SLOWLYlower frame onto air springs (2, figure 9-2). Becertain frame aligns with air spring stud andtube.

24. Install washers (4) and locknuts (3) theninstall fitting (12) and connect air hose (1).

25. Install track rod (16) using bolts (14), wash-ers (15), lock nuts (13) and locknut (1 1).

26. Install shock absorbers (10) using locknutsand washers (5 and 6) and bolts, washers andlocknuts (8, 9 and 7). Tighten locknuts (5 and 7)

until washers (6 and 9) are 1-3/4 inches apart.27. Start engine and allow air pressure to buildto normal level then release parking brake. Thiswill enable slack adjuster (4, figure 9-1) to beconnected to clevis (3) using clevis pin (2) andcotter pin (1).

28. Check all air hose connections for leaksusing soapy water solution.

CAPACITY AIR SYSTEM

TOPIC 7 – AIR SYSTEM

Terminal Objective:

Upon completion of this unit, the student will be knowledgeable in the identification, pro-cedures and repairs found in the pneumatic system found on Capacity spotters.


• Identify schematics and location of components• Understand basic foundation brake prinicipals and maintenance• Identify accessories and supply and distribution of accessory air primarily

Dura-Ride and Cab suspension.

7-1

CAPACITY AIR SYSTEM

7-2

OPERATION

The Trailer Jockey tractor air system generatespressure for operation of the tractor brakes,trailer brakes, fifth wheel latch and optionalequipment such as Dura Ride air suspension.The compressor is gear driven by the engine. Apressure regulating governor and safety valvesare provided to control the pressurization of thebrake system.

Brake System

Refer to SD193 as a guide through the follow-ing paragraphs. The compressor sends airthrough check valve to wet tank. The checkvalve prevents air pressure from escaping dueto a faulty compressor.

The pressure in the wet tank is used to operatethe compressor governor to regulate the oper-ation of the compressor in order to maintain theproper system pressure. The compressed airpasses through two check valves to the primaryand secondary reservoirs.

The primary reservoir supplies air pressure tothe primary section of the treadle valve and tothe parking brake/trailer supply valve. Whenthe treadle valve is depressed, the primary sec-tion supplies air to activate the rear tractorbrakes and, through the tractor protectionvalve, activate the trailer service brakes. Theair pressure sent to the parking brake/trailersupply valve is used to release the parkingbrakes of the tractor and trailer as well as fill thetrailer air system reservoir(s).

The parking brake section of valve is used tosupply air pressure to the parking brake cham-bers to release the parking brakes. When theparking brake valve is pulled out, the air pres-sure is released allowing springs to apply theparking brake.

Quick release valves are installed in the brakechamber supply lines to ensure the air pressure

is released instantly when the brake pedal ortreadle valve is released.

The tractor protection valve serves to isolatethe tractor air system from the trailer air systemin the event of a pressure loss in the trailer. Thismaintains air pressure to keep the tractorbrakes functioning.

The parking brake quick release valve incorpo-rates a compensator valve which allows theservice brake pressure to release the parkingbrakes as the service brakes are applied. Thisreduces the load on the brake actuating mech-anisms.

Air Suspension

On tractors equipped with optional air suspen-sion, air pressure is routed through the brakepressure protection valve to the air suspensionreservoir. The brake pressure protection valveassures the brake system is fully pressurizedBEFORE pressure is supplied to the air sus-pension system.

The leveling valve controls the flow of air pres-sure to and from the air springs. A mechanicallinkage is used to connect the leveling valve tothe rear suspension trailing arm. As weight onthe fifth wheel increases, the tractor frame set-tles causing the linkage to open the valve andsupply the air springs with additional pressureto compensate.

Air Tanks

All compressors pass a certain amount of oil inorder to lubricate the cylinder walls and pistonrings. Also, depending on the humidity, airentering the compressor contains a certainamount of water. This oil and water normallyenters the air tanks in the form of vaporbecause of the heat generated during compres-sion. After reaching the air tanks they condenseto form water emulsion that must be drained offbefore entering the brake system.

CAPACITY AIR SYSTEM

Automatic Drain

The air tanks are equipped with an automaticdrain valve. When the brakes are applied andthe pressure in the air tank drops approximate-ly 2 psi the automatic drain valve will openmomentarily allowing a small amount of air toescape. When this happens any collection of oiland water emulsion will also escape.

Manually drain automatic drain valve daily bydepressing plunger in drain exhaust port.

Operation of the automatic drain valve shouldbe checked every 250 hours of operation. Thisshould be done with the engine operating andthe brake system at normal operating pressure.

NOTE

It will be necessary for someone to observe theautomatic drain valve to perform this check.

When the operator applies the brakes, theautomatic drain valve should be checked to seethat a small amount of air escapes from thevalve.

CAUTION

If the automatic drain valves are not operatingproperly, and are not checked, the accumula-tion of water in the tanks can fill them to theextent that the brakes will not work.

All hoses, lines, and fittings should be checkedperiodically for leaks and serviceable condition.

CAUTION

Any abnormal operation of the brakes or brakesystem should be checked immediately.

The automatic drain valve should be removedand cleaned every 6 months.

a. Set the parking brake.

b. Bleed the air pressure from the brakesystem by applying and releasing the servicebrakes.

c. Depress the plunger in the automaticdrain valve to ensure that all pressure isreleased.

Disassembly and Cleaning(Refer to Figure 6-2)

Perform the following procedures to disassem-ble and clean the automatic drain valves.

a. Remove the four capscrews (1, Figure3) and lockwashers (2).

b. Remove cover (3) and sealing ring(4).

c. Remove inlet and exhaust valve (5).

d. Remove adapter and filter assembly(6).

e. Remove filter retainer (7) and filter (8).

f. Clean and inspect the filter. Replacethe filter if it is clogged.

g. Wipe all rubber parts clean. Cleaningsolvent may be used on metal parts.

Reassembly(Refer to Figure 6-2)

Perform the following procedures to reassem-ble the automatic drain valve.

a. Apply a light film of grease on thevalve seat (9).

CAUTION

Do not apply oil or grease to the inlet andexhaust valve.

b. Place sealing ring (4) in groove ofcover (3).

7-3

CAPACITY AIR SYSTEM

c. Place valve guide (10) over inlet andexhaust valve (5).

d. Place valve guide (10) and inlet andexhaust valve assembly (5) into cover (3) withwire stem (11) projecting through exhaust port(12).

e. Place cover (3) on body (13) andinstall lockwashers (2) and capscrew (1).

f. Install filter (8) in adapter and screw infilter retainer (7).

g. Install adapter and filter assembly (6)in body (13) and tighten.

h. Reinstall the automatic drain valve inthe air tank.

Air Brake System Tests

The following tests of the brake system shouldbe performed periodically to determine the con-dition of the system. These tests are designedto help discover sluggish performance and/orsystem leaks before they become a major prob-lem. Performing these tests does NOT, howev-er, rule out the importance and necessity of

functional, dynamic controllability tests andother tests required in assuring vehicle safetyand performance.

a. Checking Pressure Buildup. LowPressure Warning Cutoff, and Governor Cut-out.

(1) Open reservoir drain valves anddrain system to 0 pressure.

(2) Start engine and run at fast idle. Lowpressure warning should be on.

(3) Begin timing pressure buildup whensystem pressure reaches 50 PSI. Be ready tonote pressure at which warning cuts off. Cutoffshould occur at approximately 60 PSI.

(4) Note time when pressure reaches 90PSI. Buildup from 50-90 PSI should not takemore than 5 minutes.

(5) Continue observing gauge and notepressure at which governor cuts out. The pres-sure should be approximately 120 PSI.

b. Checking Reservoir Air SupplyLeakage.

Figure 6-2

7-4

CAPACITY AIR SYSTEM

(1) Run engine to allow system to buildto full pressure. Shut down engine.

(2) After allowing the pressure to stabi-lize for at least one minute, observe the pres-sure while timing two minutes.

(3) Drop in pressure should not exceed2 PSI in one minute (3 PSI if trailer connected).

c. Checking Service Air DeliveryLeakage.

(1) With system at full pressure andengine stopped apply foot brake valve andallow one minute for pressure to stabilize.

(2) Hold foot brake valve applied andobserve the pressure gauge and time for twominutes.

(3) Drop in pressure should not be morethan 3 PSI in one minute (4 PSI trailer connect-ed).

d. Checking Automatic Parking System.

(1) Build system pressure above 85 PSIand shut off engine.

(2) Apply and release service brake untillow pressure indicator comes on (approximate-ly 65 PSI.

NOTE

The low pressure indicator should come onbefore automatic emergency brakes apply.

(3) Continue foot brake applications untilautomatic parking brakes apply. Note gaugepressure.

(4) Automatic application should occurbelow 60 PSI.

Brake Adjustment

a. A schedule for the periodic cleaning,inspection and lubrication of brake equipmentshould be established by the operator on thebasis of past experience and severity of opera-tion. Linings and drums are parts particularlysubject to wear degradation. To compensate forthis wear, the brakes are equipped with auto-matic slack adjusters to maintain satisfactoryoperation and maximum safety. The adjustersshould be routinely checked to provide uniformlining clearance, correct travel of levers andproper equalization.

b. Brakes should be cleaned, inspected,lubricated and adjusted each time the hubs areremoved.

c. See “Slack Adjustment” section tocheck and adjust slack adjusters.

Air Pressure Adjustment(Refer to Figure 6-3)

a. Operating Test.

(1) Start the vehicle engine and build upair pressure in the air brake system and checkthe pressure registered by a dash or test gaugeat the time the governor cuts-out, stopping thecompression of air by the compressor. The cut-out pressure should be at 120 psi.

(2) With the engine still running, make aseries of brake applications to reduce the airpressure and observe at what pressure thegovernor cuts-in the compressor. As in the caseof the cut-out pressure, the cut-in pressureshould be between 90-105 psi.

NOTE

Never condemn or adjust the governor pres-sure settings unless they are checked with anaccurate test gauge or a dash gauge that isregistering accurately.(3) If pressure adjust-ment is required perform the following:

7-5

CAPACITY AIR SYSTEM

Figure 6-3

NOTE

If the governor cover is marked nonadjustableand the adjusting stem has been sheared off,this is a nonserviceable governor and mustbe replaced with a new or remanufacturedunit.

(a) Remove the top cover and o-ring(1) from the governor (4).

(b) Loosen adjusting screw locknut (2).

(c) To raise the pressure settings, turnthe adjusting screw (3) counter-clockwise.

(d) To lower the pressure settings, turnthe adjusting screw (3) clockwise.

NOTE

Be careful not to overadjust. Each 1/4 turn ofthe adjusting screw raises or lowers the pres-sure setting approximately 4 psi.

(e) When proper adjustment isobtained, tighten the adjusting screw locknut(2) and replace the cover and o-ring (1).

NOTE

THE PRESSURE RANGE BETWEEN CUT-IN AND CUT-OUT IS NOT ADJUSTABLE.

7-6

CAPACITY AIR SYSTEM

DESCRIPTION

The function of the Bendix® AD-IP™ integralpurge air dryer is to collect and remove air sys-tem contaminants in solid, liquid and vaporform before they enter the brake system. It pro-vides clean, dry air to the components of thebrake system which increases the life of thesystem and reduces maintenance costs. Dailymanual draining of the reservoirs is eliminated.The AD-IP™ air dryer consists of a desiccantcartridge secured to a die cast aluminum endcover with a single, central bolt. The end covercontains a check valve assembly, safety valve,heater and thermostat assembly, three pipethread air connections and the purge valveassembly. The removable purge valve assem-bly incorporates the purge valve mechanismand a turbo charger cutoff feature that isdesigned to prevent loss of engine “turbo”boost pressure during the purge cycle of theAD-IP™ air dryer. For ease of serviceability, allreplaceable assemblies can be replaced with-out removal of the air dryer from its mountingon the vehicle.

The AD-IP™ air dryer has three female pipethread air connections identified as follows:

Air Connection Port ID Function/ConnectionCON 4 ...................... Control Port (purge

valve control& turbo cutoff).

SUP 11 .................... Supply Port (air in).DEL 2 ...................... Delivery Port (air out).

AIR DRYERFigure 1

7-7

CAPACITY AIR SYSTEM

OPERATION

GENERAL

The AD-IP™ air dryer alternates between twooperational modes or “cycles” during operation:the Charge Cycle and the Purge Cycle. The fol-lowing description of operation is separatedinto these “cycles” of operation.

CHARGE CYCLE (refer to Figure 4)

When the compressor is loaded (compressingair) compressed air, along with oil, oil vapor,water and water vapor flows through the com-pressor discharge line to the supply port of theair dryer body.

As air travels through the end cover assembly,its direction of flow changes several times,reducing the temperature, causing contami-

nants to condense and drop to the bottom orsump of the air dryer end cover.

After exiting the end cover, the air flows into thedesiccant cartridge. Once in the desiccant car-tridge air first flows through an oil separatorlocated between the outer and inner shells ofthe cartridge. The separator removes water inliquid form as well as liquid oil and solid con-taminants.

Air, along with the remaining water vapor, is fur-ther cooled as it exits the oil separator and con-tinues to flow upward between the outer andinner shells. Upon reaching the top of the car-tridge the air reverses its direction of flow andenters the desiccant drying bed. Air flowingdown through the column of desiccantbecomes progressively drier as water vaporadheres to the desiccant material in a processknown as “ADSORPTION.” The desiccant car-tridge using the adsorption process typicallyremoves most of the water vapor from the pres-surized air.

Dry air exits the bottom of the desiccant car-tridge and flows through the center of the boltused to secure the cartridge to the end cover.Air flows down the center of the desiccant car-tridge bolt, through a cross drilled passage andexits the air dryer delivery port through thedelivery check valve. Note: the early end coverdesigns incorporated a vertical delivery checkvalve while the newer versions have a horizon-tal check valve. Both have the same function,but the components are not interchangeable.See Figure 7.

Dry air flowing through the center of the desic-cant cartridge bolt also flows out the crossdrilled purge orifice and into the purge volume.The air dryer will remain in the charge cycleuntil the air brake system pressure builds to thegovernor cutout setting.

Figure 2

7-8

CAPACITY AIR SYSTEM

PURGE CYCLE (refer to Figure 5)

As air brake system pressure reaches thecutout setting of the governor, the governorunloads the compressor (air compression isstopped) and the purge cycle of the air dryerbegins. When the governor unloads the com-p r e s s o r, it pressurizes the compressorunloader mechanism and the line connectingthe governor unloader port to the AD-IP™ airdryer end cover control port. The purge pistonmoves in response to air pressure causing thepurge valve to open to the atmosphere and theturbo cutoff valve to close off the supply of airfrom the compressor (this will be further dis-cussed in the Turbo Cutoff Feature section).Water and contaminants in the end cover sumpare expelled immediately when the purge valveopens. Also, air which was flowing through thedesiccant cartridge changes direction andbegins to flow toward the open purge valve.Liquid oiland solid contaminants collected by the oil sep-arator are removed by air flowing from thepurge volume through the desiccant drying bedto the open purge valve. The initial purge anddesiccant cartridge decompression lasts only afew seconds and is evidenced by an audibleburst of air at the AD-IP™ air dryer exhaust. Nopurging of air should occur after 30 seconds.

The actual reactivation of the desiccant dryingbed begins as dry air flows from the purge vol-ume through the purge orifice in the desiccantcartridge bolt, then through the center of thebolt and into the desiccant bed. Pressurized airfrom the purge volume expands after passingthrough the purge orifice; its pressure is low-ered and its volume increased. The flow of dryair through the drying bed reactivates the des-iccant material by removing the water vaporadhering to it. Generally 30 seconds arerequired for the entire purge volume of a stan-dard AD-IP™ air dryer to flow through the des-iccant drying bed. The delivery check valveassembly prevents air pressure in the brakesystem from returning to the air dryer during thepurge cycle. After the 30 second purge cycle iscomplete the desiccant has been reactivated ordried. The air dryer is ready for the next chargecycle to begin. However the purge valve willremain open and will not close until air brakesystem pressure is reduced and the governorsignals the compressor to charge the system.

Figure 4 Figure 5

7-9

CAPACITY AIR SYSTEM

TURBO CUTOFF FEATURE

The primary function of the turbo cutoff valve isto prevent loss of engine turbocharger air pres-sure through the AD-IP™ air dryer in systemswhere the compressor intake is connected tothe engine turbocharger. The turbo cutoff valvealso removes the “puffing” of air out the openpurge exhaust when a naturally aspirated, sin-gle cylinder compressor, equipped with an inletcheck valve, is in use. At the onset of the purgecycle, the downward travel of the purge pistonis stopped when the turbo cutoff valve (taperedportion of purge piston) contacts its matingmetal seat in the purge valve housing. With theturbo cutoff valve seated (closed position), airin the compressor discharge line and AD-IP™air dryer inlet port cannot enter the air dryer. Inthis manner the turbo cutoff effectively main-tains turbo charger boost pressure to theengine.

PREVENTIVE MAINTENANCE

Important: Review the warranty policy beforeperforming any intrusive maintenance proce-dures. An extended warranty may be voided ifintrusive maintenance is performed duringthis period.

Figure 6

Because no two vehicles operate under identi-cal conditions, maintenance and maintenanceintervals will vary. Experience is a valuableguide in determining the best maintenanceinterval for any one particular operation.

Every 900 operating hours, or 25,000 milesor three (3) months:1. Check for moisture in the air brake system byopening reservoirs, drain cocks, or drain valvesand checking for presence of water. If moistureis present, the desiccant cartridge may requirereplacement; however, the following conditionscan also cause water accumulation and shouldbe considered before replacing the desiccant:

A. An outside air source has been used tocharge the system. This air does not passthrough the drying bed.

B. Air usage is exceptionally high and not nor-mal for a highway vehicle.

This may be due to accessory air demands orsome unusual air requirement that does notallow the compressor to load and unload (com-pressing and non-compressing cycle) in a nor-mal fashion. Check for high air system leakage.If the vehicle vocation has changed it may benecessary to upgrade the compressor size.Refer to Appendix A, Table A and the columnentitled Vehicle Vocation.

C. The air dryer has been installed in a systemthat has been previously used without an airdryer. The system will be saturated with mois-ture and several weeks of operation may berequired to dry it out.

Note: A small amount of oil in the system is normal andshould not be considered as a reason to replace thedesiccant cartridge; oil stained desiccant can functionadequately.1. Visually check for physical damage to the AD-IP™ airdryer such as chaffed or broken air and electrical linesand broken or missing parts.2. Check mounting bolts for tightness. Re-torque to 270-385 inch pounds.3. Perform the Operation & Leakage Tests listed in thispublication.

7-10

CAPACITY AIR SYSTEM

WARNING

This air dryer is intended to remove moistureand other contaminants normally found in theair brake system. Do not inject alcohol, anti-freeze, or other de-icing substances into orupstream of the air dryer. Alcohol is removed bythe dryer, but reduces the effectiveness of thedevice to dry air. Use of other substances candamage the air dryer and may void the warran-ty.

D. Location of the air dryer is too close to the aircompressor. Refer to “Locating AD-IP™ AirDryer On Vehicle” section and Appendix A,Table A, column 2 for discharge line length.

E. In areas where more than a 30 degree rangeof temperature occurs in one day, smallamounts of water can temporarily accumulatein the air brake system due to condensation.Under these conditions, the presence of smallamounts of moisture is normal and should notbe considered as an indication that the dryer isnot preforming properly.

OPERATION & LEAKAGE TESTS1. Install a pressure gauge in the #1 reservoir.Check all lines and fittings leading to and fromthe air dryer for leakage and integrity. Test thedelivery port check valve assembly by buildingthe air system to governor cutout and observinga test air gauge installed in the #1 reservoir.Note the pressure on the air gauge after gover-nor cutout pressure is reached, a rapid loss ofpressure could indicate a failed delivery portcheck valve. This can be confirmed by shuttingthe engine off, draining system pressure to apoint below governor cutin (usually not lessthan 95 psi), draining residual air pressure inthe compressor discharge line. Remove thedischarge line at the supply port of the dryer,and use soapy water to determine if air is flow-ing out of the supply port. Make sure there is noair pressure at the control port, by removing theline from the control port to the governor UNLport. The reservoir needs to have a least 50PSIG for this test. If a 1” bubble forms withinone second, the delivery check valve should berepaired. Remove the test gauge before return-ing the vehicle to service.

Figure 7

7-11

CAPACITY AIR SYSTEM

2. Check for excessive leakage around thepurge valve. With the compressor in loadedmode (compressing air), apply a soap solutionto the purge valve exhaust port and observethat leakage does not exceed a 1” bubble in 1second. If the leakage exceeds the maximumspecified, repair the purge valve assembly.3. Close all reservoir drain cocks. Build up sys-tem pressure to governor cutout and note thatAD-IP™ air dryer purges with an audibleescape of air. “Fan” the service brakes toreduce system air pressure to governor cut-in.Note that the system once again builds to fullpressure and is followed by an AD-IP™ airdryer purge.

4. Check the operation of the end cover heaterand thermostat assembly during cold weatheroperation as follows:

A. Electric Power to the DryerWith the ignition or engine kill switch in the ONposition, check for voltage to the heater andthermostat assembly using a voltmeter or testlight. Unplug the electrical connector at the airdryer and place the test leads on each of thepins of the connector with the locking latch. Ifthere is no voltage, look for a blown fuse, bro-ken wires, or corrosion in the vehicle wiring har-ness. Check to see if a good ground pathexists.

B. Thermostat and Heater OperationNote: These tests are not required except incold weather operation. Turn off the ignitionswitch and cool the thermostat and heaterassembly to below 40 degrees Fahrenheit.Using an ohmmeter, check the resistancebetween the electrical pins in the air dryer con-nector half. The resistance should be 1.5 to 3.0ohms for the 12 volt heater assembly and 6.0 to9.0 ohms for the 24 volt heater assembly.

Warm the thermostat and heater assembly toover 90 degrees Fahrenheit and again checkthe resistance. The resistance should exceed1000 ohms. If the resistance values obtainedare within the stated limits, the thermostat andheater assembly is operating properly. If theresistance values obtained are outside the stat-ed limits, replace the heater and thermostatassembly.

Figure 9

7-12

CAPACITY AIR SYSTEM

SYMPTOMS

1. Dryer is constant-ly“cycling” or purging.Dryer purges fre-quently(every 4 minutes orlesswhile vehicle isidling).

CAUSE.

A. Excessive systemleakage.

IMPORTANT: Note whetherair pressure loss is shownon dash gauge(s). Pressureloss shown on gauges iscaused by service brakesystem or componentleakage. Pressure lossNOT SHOWN on gauges iscaused by supply system orcomponent leakage.

REMEDY

A. If leakage IS SHOWN on gauges testfor excessive service brake systemleakage.Allowable leakage:Single vehicle - 1 psi/minute either serv-ice reservoir.Tractor trailer - 3 psi/minute either serv-ice reservoir. Repair and retest asrequired.

B. If leakage is NOT SHOWN ongauges test for excessive supply sys-tem leakage.

Remove drain cock or valve in supplyreservoir (wet tank) and install airgauge. Build system pressure, allow airdryer to purge and observe air gauge insupply reservoir. Pressure drop shouldnot exceed 1 psi per minute. Performtests 1 to 6 in the order presented.

AIR DRYER TROUBLESHOOTING CHART

7-13

CAPACITY AIR SYSTEM

REMEDY

1. Test fittings, hoses, lines and connec-tions. Apply soap solution to detectexcessive leakage. Tighten or replace asneeded then repeat the air dryer charge-purge cycle and observe the gaugeinstalled in the supply reservoir. If leak-age is within limits remove gauge fromreservoir and replace drain cock orvalve. If excessive leakage is detected,continue tes ing.

2. Test accessories connected to supplyreservoir. Drain all air pressure from sys-tem, disconnect all air lines leading toaccessories (fan clutch, wipers, airseats, etc.) and plug the reservoir at dis-connection point. Build air system pres-sure until air dryer purges and observesupply reservoir gauge. If leakage is nolonger excessive, repair or replace leak-ing accessory. If excessive leakage isdetected, continue testing.

3. Test governor leakage. Build systempressure to governor cut-out, turn offengine and apply soap solution to gover-nor exhaust port and around cap.Leakage should not exceed a 1 in. bub-ble in 5 seconds. Reduce system pres-sure to 80 psi or less, and re-apply soapsolution. Leakage should not exceed a 1in. bubble in 5 seconds. If excessiveleakage is detected in either test, repairor replace governor.

4. Test compressor unloader leakage.Drain all air pressure from system andremove the governor from the compres-s o r. Temporarily plug the governorunloader port or air line that mated with,or connected to, the compressor. Buildair system pressure until air dryer purgesthen IMMEDIATELY SHUT OFF THEENGINE. Observe the air gauge inthe

7-14

CAPACITY AIR SYSTEM

REMEDY

supply reservoir. If leakage is within lim-its, replace the compressor unloaders.Re-connect the governor to the com-pressor (after removing plug installed ingovernor) and retest while observingsupply reservoir gauge. If excessiveleakage is detected, continue testing.

5. Test air dryer purge valve and outlet(delivery) check valve. Drain all air pres-sure from system, remove the controlline connection at the air dryer and plugthe end of the air line leading to the gov-ernor (not the air dryer control port).Build system pressure to governor cut-out and observe air gauge. If little or nopressure drop is observed replace theair dryer check valve. If pressure dropcontinues apply soap solution to airdryer purge exhaust and purge controlport (where the control line wasremoved). Leakage should not exceeda 1 in. bubble in 5 seconds. If leakage isexcessive repair or replace purge valveassembly.

6. With gauge installed at RES port ofg o v e r n o r, pressure should not dropbelow ”Cut-In” pressure at the onset ofthe compressor “Unloaded” cycle. Ifpressure drops, check for “kinks” orrestrictions in line connected to RESport. Line connected to RES port ongovernor must be same diameter, orpreferably larger than, lines connectedto UNL port(s) on governor.

7-15

CAPACITY AIR SYSTEM

SYMPTOMS

2. Water and/or Oilin Supply or ServiceReservoir.

CAUSE.

A. Improper discharge linelength or improper line mate-rial. Maximum air dryer inlettemperature is exceeded.

B. Air system charged fromoutside air source (outsideair not passing through airdryer).

C. Air dryer not purging (seeSymptom #5).

D. Purge (air exhaust) timeinsufficient due to excessivesystem leakage (see causesfor Symptom #1).

E. Excessive air usage, dutycycle too high - Air dryer notcompatible with vehicle airsystem requirement(Improper air dryer/vehicleapplication). NOTE: DutyCycle is the ratio of time thecompressor spends buildingair to total engine runningtime. Air compressors aredesigned to build air (run“loaded”) up to 25% of thetime. Higher duty cyclescause conditions that affectair brake charging systemperformance which mayrequire additional mainte-nance. Factors that add tothe duty cycle are: air sus-pension, additional airaccessories, use of anundersized compressor, fre-quent stops, excessive leak-age from fittings, connec-tions, lines, chambers orvalves, etc.

REMEDY

A. Refer to section entitled Connectingthe Air Lines as well as Appendix A,Table A columns 1 & 2 then and checkline size and length.

B. If system must have outside air fill pro-vision, outside air should pass throughair dryer. This practice should be mini-mized.

C. See Symptom #5.

D. Check causes and remedies forSymptom #1.

E. See Appendix A, Table A, column 1,for recommended compressor sizes. Ifthe compressor is “too small” for thevehicle vocation (for example, where avehicle’s vocation has changed or serv-ice conditions exceed the original vehicleor engine OE spec’s) then upgrade thecompressor. Note: The costs incurred(e.g. installing a larger capacity com-pressor, etc.) are not covered under orig-inal compressor warranty.

Charge Cycle Time - The AD-IP™ airdryer is designed to provide clean, dryair for the brake system. When a vehi-cle’s air system is used to operate non-brake air accessories it is necessary todetermine that; during normal, dailyoperation the compressor should recov-er from governor “cut-in” to governor“cut-out” (usually 100 psi to 120 psi) in90 seconds or less at engine RPM’scommensurate with the vehicle vocation.If the recovery time consistently exceedsthis limit, it may be necessary to“bypass” the air accessory responsiblefor the high air usage.

7-16

CAPACITY AIR SYSTEM

REMEDY

An example of where a by-pass systemwould be required is when the compre-sor is used to pressurize a tank trailer forpurposes of off-loading product. Consultyour local authorized Bendix parts outletor sales representative for additionalinformation.

Purge Cycle Time - During normal vehi-cle operation, the air compressor mustremain unloaded for a minimum of 30seconds. This minimum purge time isrequired to ensure complete regenera-tion of the desiccant material. If thepurge time is consistently less than theminimum, an accessory by-pass systemmust be installed. Consult your localauthorized Bendix parts outlet or salesrepresentative for additional information.

Air Compressor Size - Although the AD-IP™ air ryer can be used in conjunctionwith larger compressors, it was designedprimarily for units rated for up to 30 CFM.It is recommended that when using theAD-IP™ air dryer with a compressorwhich has a rated displacement exceed-ing 30 CFM that an authorized Bendixparts outlet or Bendix marketing repre-sentative be contacted for assistance.

7-17

CAPACITY AIR SYSTEM

SYMPTOMS

2. Water and/or Oilin Supply or ServiceReservoir. (cont.)

CAUSE.

F. Air compressor dischargeand/or air dryer inlet temper-ature too high.

REMEDY

F. Restricted discharge line. SeeAppendix A, Table A, column 1 & 2 forrecommended sizes. If discharge line isrestricted or more than 1/16” carbonbuild up is found, replace the dischargeline. Replace as necessary.

Discharge Line Freeze-Up The dis-charge line must maintain a constantslope down from the compressor to theair dryer inlet fitting to avoid low pointswhere ice may form and block the flow.If, instead, ice blockages occur at the airdryer inlet, insulation may be addedhere, or if the inlet fitting is a typical 90degree fitting, it may be changed to astraight or 45 degree fitting. For moreinformation on how to help prevent dis-charge line freeze-ups, see BendixBulletins TCH-08-21 and T C H - 0 8 - 2 2 .Shorter discharge line lengths or insula-tion may be required in cold climates.

Insufficient coolant flow through com-pressor. Inspect coolant line. Replace asnecessary (I.D. is 1/2” min.). Inspect thecoolant lines for kinks and restrictionsand fittings for restrictions. Replace asnecessary. Verify coolant lines go fromengine block to compressor and back tothe water pump. Repair as necessary.

Restricted air inlet (not enough air tocompressor). Check compressor air inletline for restrictions, brittleness, soft orsagging hose conditions etc. Repair asn e c e s s a r y. Inlet line size is 3/4 ID.Maximum restriction requirement forcompressors is 25 inches of water.Check the engine air filter and service ifnecessary (if possible, check the air filterusage indicator).

7-18

CAPACITY AIR SYSTEM

Poorly filtered inlet air (poor air quality tocompressor). Check for leaking, dam-aged or malfunctioning compressor airinlet components (e.g. induction line, fit-tings, gaskets, filter bodies, etc.). Repairinlet components as needed. Note: Dirtingestion will damage compressor and isnot covered under warranty.

If you found excessive oil present in theservice reservoir and you did not find anyissues above, the compressor may bepassing oil.

Replace compressor. If still under war-ranty, follow normal warranty process.

G. If you found excessive oil present inthe service reservoir and you did not findany issues above, the compressor maybe passing oil. Test the compressorusing the BASIC cup method asdescribed in the Bendix compressorservice manual and referred to inAppendix A, Table A, column 5. Replacecompressor. If still under warranty, follownormal warranty process.

H. If vehicle uses Holset compressor,inspect feedback check valve for properinstallation and operation.

When replacing the desiccant cartridge,make sure desiccant cartridge assemblyis properly installed and sealing rings arein place on mounting surface of desic-cant cartridge.

G. Compressor malfunction

H. Air by-passes desiccantcartridge assembly.

SYMPTOMS CAUSE REMEDY

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CAPACITY AIR SYSTEM

I. Replace desiccant cartridge assembly.Refer to Appendix A, Table A columns 3& 4 for recommended intervals.

A. Air dryers remove water and oil fromthe air brake charging system. A smallamount of oil is normal. Check that regu-lar maintenance is being performed andthat the amount of oil in the air tanks(reservoirs) is within the acceptablerange shown on the BASIC cup (seealso column 5 of Appendix A, Table A).Replace the air dryer cartridge as need-ed and return the vehicle to service.

A. Check to determine if air is reachingsupply reservoir. Inspect for kinked tub-ing or hose. Check for undrilled orrestricted hose or tubing fittings andrepair or replace as needed.

B. Verify relief pressure is at vehicle orcomponent manufacturer specifications.Replace if malfunctioning.

C. Refer to Appendix A Table A and col-umn 3. Check compressor for excessiveoil passing and/or correct compressorinstallation. Repair or replace as neces-sary. Replace desiccant cartridge.

D. Test to determine if air is passingthrough check valve. Repair or replace.

E. Increase volume in discharge line byincreasing length or diameter. Add a pingtank (small reservoir).

F. Test governor operation and/or inspectthe control line leading from the governorUNL (unloader) port to the air dryer con-trol port.

2. Water and/or Oilin Supply or ServiceReservoir. (cont.)

3. Oil present at airdryer purge exhaustor cartridge duringmaintenance.

4. Safety valve on airdryer “popping off” orexhausting air.

I. Desiccant requiresreplacement.

A. Air brake charging systemis functioning normally.

A. Restriction between airdryer and supply (first) reser-voir.

B. Air dryer safety valve mal-function.

C. Desiccant cartridge main-tenance required.

D. Malfunctioning dischargecheck valve in end cover ofthe AD-IP™ air dryer.

E. Excessive pressure pulsa-tions from compressor.(Typical single cylinder type).

F. Governor malfunction.Missing or restricted gover-nor control line installation.


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CAPACITY AIR SYSTEM

A. With compressor loaded, apply soapsolution on purge valve exhaust, to testfor excessive leakage. Repair purgevalve as necessary.

B. Confirm failure to unload by increas-ing & decreasing engine RPM and notingchange in the rate of leakage and inten-sity of accompanying leakage sound.Repair/replace compressor unloaders.

C. Purge control line must be connectedto unloader port of governor.

D. Test heater and thermostat asdescribed in Preventative MaintenanceSection.

E. See Symptom #1.

F. Repair purge valve and housing.

A. Connect compressor discharge to airdryer supply port. Reconnect lines prop-erly.

B. Test check valve for proper operation.Repair or replace as necessary.

C. Check to determine if air passesthrough discharge line. Check for kinks,bends, excessive carbon deposits, or iceblockage.

D. Discharge line should be constantlysloping from compressor to air dryer withas few bends as possible.

E. Refer to Symptom #4, Remedies E &F.

5. Constant exhaustof air at air dryerpurge valve exhaust.(Charge mode.)

6. Can not build sys-tem air pressure.

A. Air dryer purge valve leak-ing excessively.

B. Compressor fails tounload (stop compressingair) and air dryer purgeexhaust makes “sputtering”or “popping” sound.

C. Purge control line con-nected to reservoir orexhaust port of governor.

D. Purge valve frozen open -malfunctioning heater andthermostat, wiring,

E. Excessive system leak-age.

F. Purge valve stays open -supply air leaks to controlside.

A. Inlet and outlet air connec-tions reversed.

B. Check valve between airdryer and first reservoir.

C. Kinked or blocked(plugged) discharge line.

D. Excessive bends in dis-charge line (water collectsand freezes).

E. Refer to Symptom 4,causes E & F.


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CAPACITY AIR SYSTEM

A. Missing, broken, kinked,frozen, plugged or discon-nected purge control line.

B. Faulty air dryer purgevalve.

C. See Causes, B, E, G forSymptom #4.

A. This symptom is almostalways accompanied by oneor more of Symptoms 1, 2, 3,4 and 5. See related causesfor these Symptoms above.

B. Air dryer not securelymounted. (Excessive vibra-tion.)

C. Malfunctioning or saturat-ed desiccant cartridge.

D. Compressor passingexcessive oil.

E. Desiccant cartridge notassembled properly to endcover. (Loose attachment)

A. Single cylindercompressor with highpulse cycles.

A. Inspect control line from governor UNL(unloader) port to control port of air dryer.Test to determine air flows through purgecontrol line when compressor unloaded.Check for undrilled fittings. (SeeSymptom #4, Remedy C.)

B. After determining air reaches purgevalve (Remedy A above), repair purgevalve.

C. Refer to Remedies B, E, G forSymptom #4.

A. See Causes and Remedies forSymptoms 1, 2, 3, 4 and 5.

B. Vibration should be held to minimum.Add bracket supports or change air dryermounting location if necessary.

C. Replace desiccant cartridge assem-bly.

D. Check for proper compressor installa-tion; if symptoms persist, replace com-pressor.

E. Check the torque on the desiccant car-tridge to end cover attachment. Refer toassembly section of this data sheet.

A. A slight “pinging” sound may be heardduring system build up when a singlecylinder compressor is used. If this soundis deemed objectionable, it can bereduced substantially by increasing thedischarge line volume. This can beaccomplished by adding an additionalfour feet of discharge line or adding a 90cubic inch reservoir between the com-pressor and the AD-IP™ air dryer.IMPORTANT: Do not exceed the linelengths requirements specified in thismanual.

7. Air dryer does notpurge or exhaust air.

8. Desiccant materi-al being expelledfrom air dryer purgevalve exhaust (maylook like whitish liq-uid or paste or smallbeads.)- OR -Unsatisfactory des-iccant life.

9. “Pinging” noiseexcessive duringcompressor loadedcycle.


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CAPACITY AIR SYSTEM

A. Refer to Remedy C, Symptom #1.

B. Repair or replace purge valve assem-bly.

C. Repair or replace purge valve assem-bly.

A. Faulty governor installation; no air linefrom governor to compressor or line iskinked or restricted. Install or repair airline.

10. Constant seep-age of air at air dryerpurge valve exhaust( n o n - c h a r g i n gmode.)

11. The air dryerpurge piston cyclesrapidly in the com-pressor unloaded( n o n c o m p r e s s i n g )mode.

A. Defective check valveassembly in AD-IP™ airdryer end cover.

B. Leaking Turbo Cutoffvalve.

C. Leaking purge valvecontrol piston o-ring.

A. Compressor fails to“unload”.


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CAPACITY AIR SYSTEM

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CAPACITY AIR SYSTEM

7-25

CAPACITY ABS/ATC SYSTEM

TOPIC 8 – ABS Systems

Terminal Objective:

Upon completion of this unit, the student will be knowledgeable in the description of the sys-tem and it operation. Also, understanding of individual ABS components found on Capacityspotters.


• Identify schematics and location of components• Perform ABS System diagnostics and troubleshooting

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ABS CONTROLLER

INTRODUCTION

Bendix® EC-60™ controllers are members of afamily of electronic Antilock Braking System(ABS) devices designed to help improve thebraking characteristics of air braked vehicles -including heavy and medium duty buses,trucks, and tractors. ABS controllers are alsoknown as Electronic Control Units (ECUs).

Bendix ABS uses wheel speed sensors, ABSmodulator valves, and an ECU to control eitherfour or six wheels of a vehicle. By monitoringindividual wheel turning motion during braking,and adjusting or pulsing the brake pressure ateach wheel, the EC-60™ controller is able tooptimize slip between the tire and the road sur-face. When excessive wheel slip, or wheel lock-up, is detected, the EC-60™ controller will acti-vate the Pressure Modulator Valves to simulatea driver pumping the brakes. However, the EC-60™ controller is able to pump the brakes onindividual wheels (or pairs of wheels), inde-pendently, and with greater speed and accura-cy than a driver.

In addition to the ABS function, premium mod-els of the EC-60™ controller provide anAutomatic Traction Control (ATC) feature.Bendix ATC can improve vehicle traction duringacceleration, and lateral stability while drivingthrough curves. ATC utilizes Engine TorqueLimiting (ETL) where the ECU communicateswith the engine’s controller and/or DifferentialBraking (DB) where individual wheel brakeapplications are used to improve vehicle trac-tion.

Premium EC-60™ controllers have a drag-torque control feature which reduces driven-axle wheel slip (due to driveline inertia) by com-municating with the engine’s controller andincreasing the engine torque.

8-2


POWER-UP SEQUENCE

WARNING

The vehicle operator should verify proper oper-ation of all installed indicator lamps (ABS, ATC,and trailer ABS) when applying ignition powerand during vehicle operation.

Lamps that do not illuminate as required whenignition power is applied, or remain illuminatedafter ignition power is applied, indicate the needfor maintenance.

ABS Indicator Lamp Operation

The ECU will illuminate the ABS Indicator Lampfor approximately three seconds when ignitionpower is applied, after which the lamp will extin-guish if no diagnostic trouble codes are detect-ed.

The ECU will illuminate the ABS Indicator Lampwhenever full ABS operation is not availabledue to a diagnostic trouble code. In mostcases, partial ABS is still available.

ATC Status/Indicator Lamp Operation

The ECU will illuminate the ATC lamp forapproximately 2.5 seconds when ignition poweris applied, after which the lamp will extinguish,if no diagnostic trouble codes are detected.

The ECU will illuminate the ATC Indicator Lampwhenever ATC is disabled due to a diagnostictrouble code.

Trailer ABS Indicator Lamp Operation

Certain models of the ECU will control theTrailer ABS Indicator Lamp when a PLC signal(SAE J2497) from a trailer ABS ECU is detect-ed.

ABS OPERATION

Bendix ABS uses wheel speed sensors, ABSmodulator valves, and an ECU to control eitherfour or six wheels of a vehicle. By monitoringindividual wheel turning motion during braking,and adjusting or pulsing the brake pressure ateach wheel, the EC-60™ controller is able tooptimize slip between the tire and the road sur-face. When excessive wheel slip, or wheel lock-up, is detected, the EC-60™ controller will acti-vate the Pressure Modulator Valves to simulatea driver pumping the brakes. However, the EC-60™ controller is able to pump the brakes onindividual wheels (or pairs of wheels), inde-pendently, and with greater speed and accura-cy than a driver.

Single Drive Axle Control (4x2 Vehicle)

For vehicles with a single rear drive axle (4x2),the brakes are operated independently by theEC-60™ controller, based on the individualwheel behavior.

Normal Braking

During normal braking, brake pressure is deliv-ered through the ABS PMV and into the brakechamber. If the ECU does not detect excessivewheel slip, it will not activate ABS control, andthe vehicle stops with normal braking.

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ATC OPERATION

ATC Functional OverviewJust as ABS improves vehicle stability duringbraking, ATC improves vehicle stability andtraction during vehicle acceleration. The EC-60™ controller ATC function uses the samewheel speed information and modulator controlas the ABS function. The EC-60™ controllerdetects excessive drive wheel speed, com-pares the speed of the front, nondriven wheels,and reacts to help bring the wheel spin undercontrol. The EC-60™ controller can be config-ured to use engine torque limiting and/or differ-ential braking to control wheel spin. For optimalATC performance, both methods are recom-mended.

ATC Lamp Operation

The ATC Lamp Illuminates:

1. During power up (e.g. when the vehicle isstarted) and turns off after the self test is com-pleted, providing no diagnostic trouble codesare present.

2. When ATC is disabled for any reason.

3. During an ATC event (the lamp will flash rap-idly). When ATC is no longer active, the ATCactive/indicator lampturns off.

8-4


SAFE MAINTENANCE PRACTICES

WARNING!

PLEASE READ AND FOLLOW THESEINSTRUCTIONS TO AVOID PERSONALINJURY OR DEATH:

When working on or around a vehicle, the fol-lowing general precautions should be observedat all times:

1. Park the vehicle on a level surface, apply theparking brakes, and always block the wheels.Always wear safety glasses.

2. Stop the engine and remove ignition keywhen working under or around the vehicle.When working in the engine compartment, theengine should be shut off and the ignition keyshould be removed. Where circumstancesrequire that the engine be in operation,EXTREME CAUTION should be used to pre-vent personal injury resulting from contact withmoving, rotating, leaking, heated or electricallycharged components.

3. Do not attempt to install, remove, disassem-ble or assemble a component until you haveread and thoroughly understand the recom-mended procedures. Use only the proper toolsand observe all precautions pertaining to use ofthose tools.

4. If the work is being performed on the vehi-cle’s air brake system, or any auxiliary pressur-ized air systems, make certain to drain the airpressure from all reservoirs before beginningANY work on the vehicle. If the vehicle isequipped with an AD-IS™ air dryer system or adryer reservoir module, be sure to drain thepurge reservoir.

5. Following the vehicle manufacturer’s recom-mended procedures, deactivate the electricalsystem in a manner that safely removes allelectrical power from the vehicle.

6. Never exceed manufacturer’s recommendedpressures.

7. Never connect or disconnect a hose or linecontaining pressure; it may whip. Neverremove a component or plug unless you arecertain all system pressure has been depleted.

8. Use only genuine Bendix® replacementparts, components and kits. Replacement hard-ware, tubing, hose, fittings, etc. must be ofequivalent size, type and strength as originalequipment and be designed specifically forsuch applications and systems.

9. Components with stripped threads or dam-aged parts should be replaced rather thanrepaired. Do not attempt repairs requiringmachining or welding unless specifically statedand approved by the vehicle and componentmanufacturer.

10. Prior to returning the vehicle to service,make certain all components and systems arerestored to their proper operating condition.

11. For vehicles with Antilock Traction Control(ATC), the ATC function must be disabled (ATCindicator lamp should be ON) prior to perform-ing any vehicle maintenance where one ormore wheels on a drive axle are lifted off theground and moving.

TROUBLESHOOTING THE ABS CONTROLLER

8-5


REMOVING THE EC-60™ CONTROLLERASSEMBLY

1. Turn vehicle ignition off.2. Remove as much contamination as possibleprior to disconnecting air lines and electricalconnections.3. Note the EC-60™ controller assemblymounting position on the vehicle.4. Disconnect the electrical connectors from theEC-60™ controller.5. Remove and retain the mounting bolts thatsecure the EC-60™ controller.

INSTALLING A NEW EC-60™ CONTROLLER

CAUTION!

When replacing the EC-60™ controller, verifythat the unit you are installing has the correctdefault settings. Failure to do so could result ina loss of features, such as ATC and PLC, ornoncompliance with U.S. regulations such asFMVSS 121. It is recommended to use only thecorrect replacement part number. However,most configuration settings can be alteredusing the Bendix ACom™ ABS DiagnosticSoftware program.

Verify correct operation of the EC-60™ con-troller system and indicator lamps prior to put-ting the vehicle back into service. Towing vehi-cles manufactured after March 1, 2001 mustsupport the trailer ABS indicator lamp locatedon the dash.

For further information, contact either the vehi-cle manufacturer, Bendix or your local author-ized Bendix dealer.

1. Position and secure the EC-60™ controller inthe original mounting orientation using themounting bolts retained during removal. Onframe-mount ECUs, torque the mounting boltsto 7.5 to 9 NM (66-80 in. Ibs). For cabmountunits use no more torque than is necessary to

firmly secure the ECU into position. Over-tight-ening the mounting hardware can cause dam-age to the EC-60™ controller.

2. Reconnect the electrical connectors to theEC-60™ controller.

3. Apply power and monitor the EC-60™ con-troller powerup sequence to verify proper sys-tem operation.

8-6


TROUBLESHOOTING BLINK CODESAND DIAGNOSTIC MODES

ECU DIAGNOSTICS

The EC-60™ controller contains self-testingdiagnostic circuitry that continuously checks forthe normal operation of internal componentsand circuitry, as well as external ABS compo-nents and wiring.

Active Diagnostic Trouble CodesWhen an erroneous system condition is detect-ed, the EC-60™ controller:

1. Illuminates the appropriate indicator lamp(s)and disengages part or all of the ABS and ATCfunctions.2. Places the appropriate trouble code informa-tion in the ECU memory.3. Communicates the appropriate trouble codeinformation over the serial communicationsdiagnostic link asrequired. Hand-held or PC-baseddiagnostic toolsattach to the vehi-cle diagnostic con-n e c t o r, typicallylocated on orunder the dash(see Figure 9).

BLINK CODES

Blink codes allow a technician to troubleshootABS problems without using a hand-held orPC-based diagnostic tool. Instead, informationabout the ABS system is communicated by theECU using the ABS indicator lamp to displaysequences of blinks.

Note: The ECU will not enter the diagnosticblink code mode if the wheel speed sensorsshow that the vehicle is in motion. If the ECU isin the diagnostic blink code mode and thendetects vehicle motion, it will exit the blink codemode. In addition, by operating the blink codeswitch as described below, one of several diag-nostic modes can be entered. See DiagnosticModes below.

Blink Code Switch ActivationWhen activating the blink code switch:1. Wait at least two seconds after “ignition on.”(Except when entering Reconfiguration Mode)2. For the ECU to recognize that the switch isactivated “on,” the technician must press for atleast 0.1 seconds, but less than 5 seconds. (Ifthe switch is held for more than 5 seconds, theECU will register a malfunctioning switch.)3. Pauses between pressing the switch when asequence is required, (e.g. when changingmode) must not be longer than 2 seconds.4. After a pause of 3.5 seconds, the ECU willbegin responding with output informationblinks. See Figure 10 for an example.

Blink Code TimingThe ECU responds with a sequence of blinkcodes. The overall blink code response fromthe ECU is called a “message.” Each messageincludes, depending on the mode selected bythe technician, a sequence of one or moregroups of blinks. Simply record the number ofblinks for each sequence and then use the trou-bleshooting index on page 17 for active or inac-tive trouble codes and you will be directed tothe page that provides troubleshooting informa-tion.

Figure 9

8-7


NOTE:1. Sequences of blinks illuminate the ABS indi-cator lamp for half a second, with half-secondpauses between them.2. Pauses between blink code digits are 1.5seconds.3. Pauses between blink code messages are2.5 seconds.4. The lamp remains on for 5 seconds at theend of messages.

Once the ABS indicator lamp begins displayinga sequence of codes, it continues until all blinkcode messages have been displayed and thenreturns to the normal operating mode. Duringthis time, the ECU will ignore any additionalblink code switch activation.

All trouble codes, with the exception of voltageand J1939 trouble codes, will remain in anactive state for the remainder of the powercycle.

Voltage trouble codes will clear automaticallywhen the voltage returns within the requiredlimits. All ABS functions will be re-engaged.

J1939 trouble codes will clear automaticallywhen communications are re-established.

DIAGNOSTIC MODESIn order to communicate with the ECU, the con-troller has several modes that the techniciancan select, allowing information to be retrieved,or other ECU functions to be accessed.

Diagnostic ModesTo enter the various diagnostic modes:

Active Diagnostic Trouble Code Mode

For troubleshooting, typically the Active andInactive Diagnostic Trouble Retrieval Modesare used. The technician presses the blinkcode switch once and the ABS indicator lampflashes a first group of two codes, and if thereare more trouble codes recorded, this is fol-lowed by a second set of codes, etc. (See page17 for a directory of these codes.) All activetrouble codes may also be retrieved using ahand-held or PC-based diagnostic tool, such asthe Bendix® ACom™ Diagnostics software.

8-8


To clear active diagnostic trouble codes (asproblems are fixed), simply clear (or “self-heal”)by removing and re-applying ignition power.The only exception is for wheel speed sensortrouble codes, which clear when power isremoved, re-applied, and the ECU detects validwheel speed from all wheel speed sensors.Alternately, codes may be cleared by pressingthe diagnostic blink code switch 3 times (toenter the Clear Active Diagnostic Trouble CodeMode) or by using a hand-held or PC-baseddiagnostic tool. Handheld or PC-based diag-nostic tools are able to clear wheel speed sen-sor trouble codes without the vehicle being driv-en.

Inactive Diagnostic Trouble Code Mode

The ECU stores past trouble codes and com-ments (such as configuration changes) in itsmemory. This record is commonly referred toas “event history.” When an active trouble codeis cleared, the ECU stores it in the event histo-ry memory as an inactive trouble code.

Using blink codes, the technician may reviewall inactive trouble codes stored on the ECU.The ABS indicator lamp will display inactivediagnostic blink codes when the diagnosticblink code switch is depressed and releasedtwo times. See troubleshooting guide page toread for help. Inactive trouble codes, and eventhistory, may be retrieved and cleared by usinga hand-held or PC-based diagnostic tool, suchas the Bendix® ACom™ Diagnostics software.

Clearing Active Diagnostic Trouble Codes

The ECU will clear active trouble codes whenthe diagnostic blink code switch is depressedand released three times.

System Configuration Check Mode

The ABS indicator lamp will display systemconfiguration information when the diagnosticblink code switch is depressed and releasedfour times. The lamp will blink out configurationinformation codes using the following patterns.(See Chart 3). In this mode the ECU tells thetechnician, by means of a series of six blinkcodes, the type of ABS system that the ECUhas been set up to expect. For example, if thefourth blink code is a three, the technicianknows that a 6S/5M sensor/modulator configu-ration has been set.

Reconfigure ECU Mode

Vehicle reconfiguration is carried out by usingthe Reconfigure ECU Mode. Note: To enter theReconfiguration Mode, the blink code switchmust be heldin before the application of ignitionpower. Once the power is supplied, the switchis released and then pressed seventimes.

8-9


Bendix® ACom™ Diagnostics 3.0 SoftwareBendix® ACom™ Diagnostics is a PC-basedsoftware program and is designed to meet RP-1210 industry standards. This software pro-vides the technician with access to all the avail-able ECU diagnostic information and configura-tion capability, including:

• ECU information• Diagnostic trouble codes and repair informa-

tion• Configuration (ABS, ATC, and more)• Wheel speed information• Perform component tests• Save and print information

When using ACom™ Diagnostics software todiagnose the EC-60 ABS ECU, the computer’sserial or parallel port needs to be connected tothe vehicle’s diagnostic connector. For moreinformation on ACom™ Diagnostics software orRP1210 compliant tools, go towww.bendix.com or visit your local authorizedBendix parts outlet.

See J1587 SID and FMI codes and their Bendixblink code equivalents

www.bendix.comVisit Bendix online for the latest information,and ways to find the Bendix contacts you need.Contact technical support, service engineers,Bendix account managers, and more —w w w.bendix.com is your complete Bendixresource.

Bendix Technical Assistance TeamFor direct telephone technical support, call theBendix technical assistance team at:

1-800-AIR-BRAKE (1-800-247-2725),Monday through Friday, 8:00 A.M. to 6:00 P.M.EST, and follow the instructions in the recordedmessage. Or, you may e-mail the Bendix tech-nical assistance team at: [email protected].

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8-21


ABS/ATC WIRING

CAB ECU Wiring Harness ConnectorsThe in-cab EC-60™ controllers are designed tointerface with AMP MCP 2.8 connectors as refrenced in Chart 4. Follow all AMP requirementsfor the repair of wire harnesses.

All wire harness connectors must be properlyseated. The use of secondary locks is stronglyadvised.

CAUTION

All unused ECU connectors must be coveredand receive proper environmental protection.

Frame ECU Wiring Harness ConnectorsFrame-mount EC-60™ controllers aredesigned to interface with Deutsch connectorsas referenced in Chart 4.

CAUTION

The frame wire harness connectors must beproperly seated with the seals intact (undam-aged). All unused connector terminals must beplugged with the appropriate sealing plugs.Failure to properly seat or seal the connectorscould result in moisture or corrosion damage tothe connector terminals. ECUs damaged bymoisture and/or corrosion are not coveredunder the Bendix warranty. Secondary locksmust be snapped securely in place. Follow allDeutsch requirements for the repair of wire har-nesses.

CAUTION

All unused connector terminals must beplugged with the appropriate sealing plugs.Frame ECU Connector Covers Frame ECUsare provided with covers that must be removed

to permit connection of the vehicle wiring har-ness. The cover can be removed by sliding theslide lock mechanism to the unlock position.

The covers provide strain relief and connectorprotection of the vehicle wire harness and willaccept round convoluted conduit with an I.D.of 19 mm.

ABS Wiring RequirementsAs a matter of good practice and to insure max-imum system robustness, always use the max-imum size wire supported by the wire harnessconnectors for battery, ignition, ground, PMV,TCV, Interaxle Differential Lock and indicatorlamp circuits.

All sensor and serial communications circuits(J1587 and J1939) must use twisted pair wiring(one to two twists per inch). See the appropri-ate SAE document for additional details.

WARNING

All wires must be carefully routed to avoid con-tact with rotating elements. Wiring must beproperly secured approximately every 6 to 12inches using UV stabilized, non-metallic hoseclamps or bow-tie cable ties to prevent pinch-ing, binding or fraying.

It is recommended that wires be routed straightout of a connector for a minimum of three inch-es before the wire is allowed to bend.

Battery and ground wires should be kept to aminimum length.

If convoluted tubing is used, its I.D. must matchthe size of the wire bundle as closely as possi-ble.

TROUBLESHOOTING WIRING

8-22


CAUTION

Wire harness lengths must be carefully select-ed for the vehicle. Harnesses that are too longincrease the possibility of electrical interferenceand wire damage. Excess lengths of wire arenot to be wound to form coils, instead re-route,repair or replace wire harness. Do not attemptto stretch harnesses that are too short, sincemechanical strain can result in wire breakage.

Wheel Speed Sensor WiringRoute sensor wiring coming out of the wheelends away from moving brake components.Sensor wiring needs to be secured to the axleto prevent excess cable length and wiring dam-age. It is required that cable ties be installed tothe sensor wire within 3 inches (76.2 mm) ofthe sensor head to provide strain relief.

Following the axle, the sensor wires must beattached along the length of the service brake

hoses using cable ties with ultraviolet protec-tion and secured every 6 to 8 inches (152 to203 mm). Sufficient – but not excessive – cablelength must be provided to permit full suspen-sion travel and steering axle movement. Installwires so that they cannot touch rotating ele-ments such as wheels, brake discs or driveshafts. Radiation protection may be necessaryin the area of brake discs.

Bendix does not recommend using standardtie-wraps to secure wiring harnesses directly torubber air lines. This may cause prematurewiring failure from the pressure exerted on thewiring when air pressure is applied through theair line. Non-metallic hose clamps or bow-tietie-wraps are preferred.

The use of grommets or other suitable protec-tion is required whenever the cable must passthrough metallic frame members.

8-23


All sensor wiring must utilize twisted pair wire,with approximately one to two twists per inch.

It is recommended that wires be routed straightout of a connector for a minimum of three inch-es before the wire is allowed to bend.

8-24


ABS — Antilock Brake System.ABS Event — Impending wheel lock situation thatcauses the ABS controller to activate the modulatorvalve(s).ABS Indicator Light — An amber light which indi-cates the operating status of an antilock system.When the indicator lamp is on, ABS is disabled andthe vehicle reverts to normal brake operation.Air Gap — Distance between the Sensor and tonering.ASR — Automatic Slip Regulation. Another namefor traction control.ATC — Automatic Traction Control. An additionalABS function in which engine torque is controlledand brakes are applied differentially to enhancevehicle traction.ATC Light — A light that indicates when tractioncontrol is operating.Channel — A controlled wheel site.CAN — Controller Area Network. J1939 is an SAEversion of the CAN link.Clear Codes — System to erase historical diagnos-tic trouble codes from the ECU, from either theDiagnostic Switch or from a hand-held diagnostictool (only repaired diagnostic trouble codes may becleared).Configuration — The primary objective is to identi-fy a “normal” set of sensors and modulators for theElectronic Control Unit, so that it will identify futuremissing sensors and modulators.Diagnostic Connector — Diagnostic receptacle invehicle cab for connection of J1587 hand-held orPC based test equipment. The tester can initiatetest sequences, and can also readsystem parameters.Diagnostic Switch — A switch used to act vateblinks codes.Differential Braking — Application of brake forceto a spinning wheel so that torque can be applied towheels which are not slipping.ECU — Electronic Control Unit.Diagnostic Trouble Code — A condition that inter-feres with the generation or transmission ofresponse or control signals in the vehicle's ABS sys-tem that could lead to the functionality of the ABSsystem becoming inoperable in whole or in part.FMVSS-121 — Federal Motor Vehicle SafetyStandard which regulates air brake systems.

IR – Independent Regulation. A control method inwhich a wheel is controlled at optimum slip, a pointwhere retardation and stability are maximized. Thebrake pressure that is best for the wheel in questionis directed individually into each brake chamber.J1587 — The SAE heavy duty standard diagnosticdata link.J1708 — An SAE standard which defines the hard-ware and software protocol for implementing 9600baud heavy vehicle data links. J1587 version of aJ1708 data link.J1939 — A high speed 250,000 baud data link usedfor communications between the ABS ECU engine,transmission and retarders.MIR — Modified Independent Regulation. A methodof controlling the opposite sides of a steer axle dur-ing ABS operation so that torque steer and stoppingdistance are minimized.PLC — Power Line Carrier. The serial communica-tion protocol used to communicate with the trailerover the blue full time power wire.PMV — Pressure Modulator Valve. An air valvewhich is used to vent or block air to the brake cham-bers to limit or reduce brake torque.QR — Quick Release. Quick release valves allowfaster release of air from the brake chamber after abrake application. To balance the system, quickrelease valves have hold off springs that producehigher crack pressures (when the valves open).Relay Valve — Increases the application speed ofthe service brake. Installed near brakes with largerair chambers (type 24 or 30). The treadle valve acti-vates the relay valve with an air signal. The relayvalve then connects its supply port to its deliveryports. Equal length air hose must connect the deliv-ery ports of the relay valve to the brake chambers.Retarder Relay — A relay which is used to disablea retarder when ABS is triggered.Sensor Clamping Sleeve — A beryllium coppersleeve which has fingers cut into it. It is pressedbetween an ABS sensor and mounting hole to holdthe sensor in place.Stored Diagnostic Trouble Codes — A diagnos-tic trouble code that occurred.TCS — Traction Control System, another name forATC or ASR.Tone Ring — A ring that is usually pressed into awheel hub that has a series of teeth (usually 100)and provides actuation for the speed sensor. Notemaximum run out is .008.

GLOSSARY

8-25


8-26


8-27

CAPACITY CHASSIS LUBRICATION SYSTEM

TOPIC 9 – Chassis Lubrication System

Terminal Objective:

Upon completion of this unit, the student will be knowledgeable in the lubrication sys-tem and its operation which is found on Capacity spotters.


• Identify schematics and location of components• Perform Lubrication System diagnostics and troubleshooting

9-1


SYSTEM DESCRIPTION

The Grease Jockey ® system is controlled by atimer, which activates either an air solenoidvalve or an electric motor to drive a pump. Thepump supplies grease into the main supply linefor delivery to localized distribution modules.

These modules are made up of manifolds withmetering valves and distribution lines for eachlube point in that localized area. The meters aredesigned to dispense a precise amount ofgrease at each lube cycle. Meter size is chosenby a ratio of the smallest to largest lube pointrequirements in the system.

The pump must pressurize the system, thenvent it to allow the metering valves to reset forthe next cycle. A fluid grease is required toachieve proper flow and lubrication characteris-tics.

SYSTEM COMPONENTS

TIMER

The timer (Ref. Fig.1) on an air operatedpump system is acompact solid statedevice housed in ahigh impact resistantplastic enclosure. Ithas seven lube cycleinterval settings from

1/2 to 6 hours, plus a test position and a man-ual run button.

The timer operates the system only while thevehicle's ignition is turned on. A memory func-tion keeps track of elapsed-cycle-time even ifthe ignition switch is turned off. When the pre-determined cycle time has elapsed, the timersignals the pump to initiate a lubrication cycle.If the vehicle's ignition is turned off before theinterval is complete, the timer's memory "holds"the time count until the vehicle is restarted.

When the cycle-time dial is switched from onerange to another, the manual run button shouldbe pressed to initiate the new cycle time setting(otherwise, the new time is added to any timethat remains from the previous lube cycle).

When rapid repetitive cycles are needed, setthe cycletime dial to the "test" position andpress the manual run button. In this mode thetimer signals the pump to cycle approximatelyonce every minute. (45 seconds on and 15 sec-onds off). This rapid cycling continues as longas the timer remains in the "test" position.Always reset the timer dial to it's proper setting.

SOLENOID

The air valve (Ref. Fig. 3)used with the air operatedpump threads into theport on the bottom of thepump. It is a 3-way, nor-mally closed, free ventingvalve available with eithera 12 or 24 VDC 9 watt

continuous duty rated coil. The coil is moldedand potted with a 6" lead of 16 AWG wire and aweather tight (male) conne tor. The air valvehas a 1/8" NPT inlet port and a 1/4" NPT malethread outlet port. The maximum operatingpressure is 150 psi. The barbed connector isthe exhaust port and should not be blocked.There is a manual test button located on theend above the electrical lead. A 22' wireharness with a weather tight (female) connectorto mate with the solenoid is available (includedwith kits).

9-2


AIR OPERATED PUMP

The air pump (Ref. Fig. 4) operates when the 3-way air solenoid valve is actuated by the timerand air pressure is applied to the air chamberport (1) and diaphragm (2). This forces thespring-loaded pump piston (3) upward com-pressing the grease in chamber (4). This pres-sure seats the flapper valve (5) against thereservoir opening (6) and grease flows towardport (9).

Simultaneously, pressure is applied behind thespringloaded check valve poppet (8) throughport (9) sealing off passage way (7). Greaseflows into the main lines through outlet (11).

After completion of an on-time cycle, the 3-wayair valve exhausts the air in the pump. Thepump piston spring forces the pump piston (3)down allowing the flapper valve (5) to unseatfrom the reservoir opening (6). Grease from thereservoir is drawn into chamber (4) just vacat-ed by the pump piston (3). System pressure isrelieved through port (9) to port (7) back to thereservoir as check valve (8) is returned byspring (10).

MODULES

A module is (Ref. Fig. 5) an assembly that dis-tributes the grease from the main line to agroup of lube points. It is made up of a mani-fold, mounting stem, meters (metering valves),3/16" OD tubing, and fittings. One manifold canhold as many as 12 meters. Plugs are availableto close off any manifold port that is notrequired. The manifold mounts with the portedstud through a 5/8" hole. Main lines may beconnected at either end of the manifold or atthe end of the mounting stud.

METERS

Meters (Ref. Fig. 6) are positive displacement,springreloaded, dispensing devices designedfor use in Grease Jockey systems operating at900 to 1200 psi. These meters are available in6 sizes (based on output volume) to meet vari-ous lube requirements. These 6 sizes provideadequate choices to supply every lube point ona truck chassis, including the fifth wheel. (SeeFig. 7)

Request Lubriquip document GJ-00003 foradditional meter information. RequestLubriquip document GJ-00006 for instructionon changing meter volume.

9-3


TUBING

Only Grease Jockey heavy wall nylon tubingshould be used in the system. Use 3/16" ODlines for lube point distribution and 5/16" ODfor main lines with brass fittings. (Tube insertsare required on ALL 5/16" line connections).Other adapters, fittings, connectors, andmounting hardware are available fromLubriquip.

CAUTION

DO NOT substitute air brake tubing for lubelines. The pressure rating is NOT adequate forGrease Jockey lubrication system use.

GREASE

A fluid lithium grease of NLGI grade "0" or "00"with an "EP" additive is standard for this typesystem. Lubriquip 550-400-020 is availablefrom your Grease Jockey distributor. Greaseshould not contain suspended lubricatingagents such as graphite or moly disulfide.

Request Lubriquip document GJ-00003 foradditional grease information.

9-4


9-5


Purging air from the main line:

Note: Check the vehicle air supply. At least 100PSI gauge pressure is required. All the air mustbe removed from the main line and manifolds.Follow the next 5 steps carefully.

1) All of the 1/4" NPT end port and 1/8" NPTstud plugs on the module manifolds shouldbe removed.

2) With the vehicle ignition switch turned ON.Set timer at the test position and press themanual run button.

3) As the pump cycles , check the open moduleports for flow of grease with no air.

4) When the flow of grease from a port is freeof air close the port and continue thisprocess until all ports have been checked.Check the open port closest to the pump firstproceeding to the port furthermost from thepump last. This will push out the air in themain line(s).

Note: The 3/16" distribution lines are pre-filled.They should not require purging of air.

5) Let the system run in the test position for afew minutes. Check all line connections tobe sure they are holding pressure. Check atlube points to be sure lubricant is moving tothis point in the system.

At this point the system should be running cor-rectly and you should reset the timer to thedesired setting for your application.

Timer settings are dependent upon your appli-cation. As a starting point refer to Fig. 2.

If any part of the system has not functioned asit should please refer to the troubleshootingsection.

9-6


9-7


9-8

CAPACITY HYDRAULIC SYSTEM

TOPIC 10 – Hydraulic System

Terminal Objective:

Upon completion of this unit, the student will be knowledgeable in the hydraulic systemand its operation which is found on Capacity spotters.


• Identify schematics and location of components• Understand specific topics such as cylinder rebuild, valve pressure adjustment

and fifth wheel lift cable adjustment.• Perform Hydraulic System diagnostics and troubleshooting

10-1


10-2

DESCRIPTION

The hydraulic system consists basically of a hydraulic reservoir, hydraulic pump, control valve,actuating cylinders, a filter, hoses, fittings and pilot check valve.

Oil is drawn from the reservoir by the transmission mounted pump (Figure 10-1) and sent to thecontrol valve. The pressurized oil can be directed to the boom cylinders or when not needed theoil returns to the tank via the return filter.

Figure 10-1


10-3

Checking Oil Level

NOTE

Always check and service hydraulic reservoirwith fifth wheel POWERED down to fully low-ered position.

Refer to Figure 10-2. The level of fluid shouldbe checked daily. The fluid level should bemaintained between the red and the black linesin the sight gauge. Add oil as necessary.

NOTE

Refer to the table of recommended lubricants atthe beginning of this manual for the type of oilto be used

Hydraulic System Filters

a. Return Filter. The hydraulic return fil-ter is the spin-on type. The filter is locatedinside the frame rail, behind the reservoir andshould be changed with each change of fluid.Perform the following procedures to replace thereturn filter.

(1 ) Provide a suitable container to catchoil spill then, remove the return filter (1, figure10-3) from filter head (2).

(2) Apply a thin film of oil to the filter gas-ket (3) then thread the filter (1) onto the filterhead (2).

(3) Tighten filter (1) by hand 1/2 to 3/4turn after gasket (3) contacts filter head (2).

(4) Operate the hydraulic system andcheck for leaks.

(5) Dispose of used filter and oil inaccordance with federal and local regulations.

b. Suction Filter. The suction filter shouldbe removed and cleaned when the hydraulic oilis changed. Refer to the Lubrication Chart inSection 1 of this manual for the recommendedservice interval and the type of oil to be usedand perform the following procedures tochange the oil.

Changing the Hydraulic Oil

NOTE

Hydraulic oil should be changed while it is stillwarm.

a. Raise the boom to its maximum heightthen allow it to lower using its weight. Do NotPOWER it down.

b. Provide a suitable container to catchthe drained oil then remove the drain plug (4,Figure 10-3). Once all oil has drained, reinstallplug.

c. Remove bolts (5), lockwashers (6),cover (7) and gasket (8).

d. Unscrew suction filter (10) from filterhead and remove it from reservoir (9).

Figure 10-2


10-4

WARNING

Using compressed air can create airborne par-ticles that may enter the eyes. Always use eyeprotection when using compressed air.

e. Clean the suction filter (10) by agitat-ing it in solvent then dry with filtered com-pressed air.

f. Inspect interior of reservoir (9) andclean if necessary.

g. Reinstall suction filter (10).

h. Discard old gasket (8). Positionreplacement gasket (8) on reservoir (9) theninstall cover (7), bolts (5) and lockwashers (6).

i. Remove breather cap (11 ) and servicereservoir (9) with specified oil up to black lineon oil level sight gauge (Figure 10-2).

j. Check filter screen (12, Figure 10-3).

k. Install breather cap then start engineand operate hydraulic system to bring oil to nor-mal operating temperature.

l. Recheck level as described earlier inthis section. Add oil as necessary to maintainproper level.

m. Check for leaks.

Inspection

The entire hydraulic system should be checkedfrequently for leaks, loose fittings and damage.Refer to the Periodic Maintenance for recom-mended inspection intervals.

Hydraulic Relief Valve Adjustment

The hydraulic relief valve must be adjusted orchecked when the hydraulic system pressurewill not lift the fifth wheel boom and any time thehydraulic control valve is replaced.

Adjustment of the hydraulic relief valve pres-sure involves adjusting the hydraulic controlvalve pressure setting. This procedure willrequire an assistant to operate the fifth wheelboom control during this adjustment. Thehydraulic control valve is mounted on top of thetransmission.

a. Refer to Figure 10-4 and remove theacorn nut to expose the adjusting screw of thehydraulic control valve.

b. Remove hose A from fitting B.Plug/clamp hose. Install gauge on fitting B.

11

125

67

8

9

4

2

3

1

4

10

Figure 10-3


10-5

c. Start the engine and warm thehydraulic oil to its normal operating tempera-ture.

d. With the engine at approximately 1/4throttle, lower the fifth wheel to the limit of itstravel while watching the hydraulic pressuregauge.

CAUTION

Do not hold the fifth wheel boom lift at its limit oftravel for more than necessary or 30 seconds ata time. Holding the system at relief pressure willoverheat the oil quickly. If more time is needed,allow the oil to cool between adjustments.

e. Adjust the control valve relief bythreading adjusting screw IN to increase pres-sure, OUT to decrease pressure. Adjust screwto 2500 psi then tighten jam nut and installacorn nut. Remove plug and install hose “A”on fitting “B”.

TO BOTTOM OF BOOMLIFT CYLINDERTO TOP OF BOOM LIFT

CYLINDER HYDRAULIC CONTROLVALVE

COUNTERBALANCE VALVE

HOSE “A”

FITTING “B”

PLUG

JAM NUT

ACORN NUT

CONTROL CABLE

ADJUSTING SCREW

0-3000 PSI GAUGE

Figure 10-4


10-6

HYDRAULIC SYSTEMREPAIR

The following paragraphs outline proceduresfor replacement and/or repair of major compo-nents of the hydraulic system. Refer to the fig-ures as indicated for location and identificationof parts when performing these procedures.

HYDRAULIC TANK

All serviceable components of the hydraulictank may be removed without removing thetank.

1. Removal.

a. Refer to Figure 10-5. Provide a suit-able container to catch drained oil then removedrain plug (1) and cap (2).

b. Once oil has drained, reinstall cap (2)and plug (1). Dispose of used oil in accordancewith federal and local regulations.

c. Loosen clamp (3) then unscrew filterassembly (4) from tank (9). Plug open part of fil-ter assembly to prevent entry of dirt.

d. Remove clamp (5) and disconnecthose (6) from adapter (10).

e. Remove bolts and lockwashers (7 and8) to remove hydraulic tank (9).

f. Remove adapter (10).

2. Installation.

a. Position the hydraulic tank (9) on vehi-cle frame and install bolts and lockwashers (7and 8).

b. Install adapter (10) then, attach hose(6) and secure with clamp (5).

c. Thread filter assembly (4) onto tank(9). Once filter assembly is tight, tighten clamp(3).

d. Make certain drain plug (1) is tightthen, remove cap (2) and fill tank to full mark onlevel gauge (11).

e. Start engine and operate boom upand down several times to expel trapped airand check for leaks.

f. Power boom down then, replenishtank to full mark.

HYDRAULIC BOOM LIFT PUMP

1. Removal.

a. Remove the two walk ways behindcab.

b. Drain the hydraulic tank.

c. Refer to Figure 10-6 and disconnecthydraulic hose (1). NOTE: The hydraulic pumpis mounted on the PTO located on right side oftransmission.

d. Remove clamps (3) and hose (4).

Figure 10-5


10-7

e. Remove bolts (7) and lockwashers (8)to remove pump (9).

f. Remove adapter (5), elbow (6) andstraight fitting (2).

2. Shaft Seal Replacement.

a. Use a stiff bristled brush and solventto clean outside of pump thoroughly. Use com-pressed air to remove contaminants from shaftseal area.

b. Refer to figure 10-10 and removesocket screws (6), lockwashers (7) and mount-ing adapter (8).

c. Remove capscrews (1) and lockwash-ers (2).

d. Hold gear housing (4) and rear cover(3) together then tap front flange (5) with plas-tic hammer to loosen.

e. Slide front flange (5) off gear shaftsthen remove o-ring (12), seal (14) and backupseal (15)).

f. Install front flange (5) in machinist'svise using cardboard between jaws of vise and

flange.

CAUTION

Do not allow the punch to rest against the sealbore or bearing while driving the seal (9) out.

g. Slide a punch of appropriate sizethrough the bearing and against the seal'smetal casing. Hold the punch away from thebearings and drive the seal (9) out without dam-aging seal bore or bearing. Move the puncharound the seal as it is driven out. (Figure 10-7)

Figure 10-6

Figure 8-7


10-8

h. Check around seal bore for scratches.Use 400 grit sand paper or finer to clean uplight scratches. If bore is badly scratched,flange must be replaced.

i. Wash front flange (5, Figure 10-10) inclean solvent and use compressed air to dry.

j. Press replacement seal (9) into frontflange (5) as shown in Figure 8-8. Be certainNOT to press against protruding ends of shaftbearings.

k. Once upper wood block is againstfront flange, remove wood block and installsocket wrench with outside diameter just slight-ly smaller than seal bore against seal.

I. Continue pressing seal into bore until itjust clears snap ring groove in seal bore.

m. Apply 2 or 3 drops of #290 Loctite.against seal bore and outside of seal (9). AllowLoctite to flow entirely around seal O.D.

n. Wipe any excess Loctite. from sealbore and from seal lip.

o. Install o-ring (12), backup seal (15)and seal (14). Use clean heavy grease to holdseals and o-ring in place.

p. Coat splined end of drive shaft withclean grease to protect seal (9).

q. Install front flange (5) on pump andsecure with capscrews (1) and lockwashers (2).Tighten capscrews to 75 ft.lbs. torque.

r. Install mounting adapter (8), socketscrews (6) and lockwashers (7).

3. Disassembly.

a. Use a stiff bristled brush and solventto clean outside of pump thoroughly.

b. Use an ink marker to make alignmentmarks on the housing pieces nearest to driveshaft extension side for reference duringassembly (Figure 10-9).

c. Refer to Figure 10-10 and removesocket screws (6) and lockwashers (7) torelease mounting adapter (8).

d. Remove capscrews (1) and lockwash-ers (2).

e. Use a wood mallet or plastic hammerto tap rear cover (3) loose, then remove rearcover.

f. Remove o-ring (12), seal (14) andbackup seal (15) from rear cover (3).

Figure 10-8

Figure 10-9


10-9

Figure 10-10


10-10

g. Remove thrust plate (13) then removeo-rings (20) from thrust plate.

h. Mark tooth and valley with layout dyefor reference during assembly.

Figure 10-10. Hydraulic Pump Disassembly

i. Remove drive gear (11) and idler gear(10) straight out of gear housing (4).

j. Tap edges of gear housing (4) withwooden mallet or plastic hammer to loosenthen separate gear housing (4) and front flange(5).

k. Dowels (18 and 19) are pressed intogear housing (4) and need not be removedunless gear housing is to be replaced. Use suit-able drift and tap alternate sides to removedowels.

I. Remove o-ring (12), seal (14) andbackup seal (15) from front flange (5).

m. Remove thrust plate (13) from gearhousing (4) then remove o-rings (21) fromthrust plate (13).

4. Inspection.

a. Visually inspect all parts. It is not nec-essary to set up gauges to check the amount ofwear on the pump parts. After a visual inspec-tion those parts which are in questionable con-dition should be replaced with new ones.

b. Note the bores in the gear plate. Onthe discharge side you will see a milled groovein the center of the plate. During the initialbreak-in at the factory, the gears cut into thesuction side. Nominal depth of this cut is .008"and should not exceed .015". Small bits ofmetal are sometimes pulled out of the surfaceduring break-in. This is not detrimental. If thecut is deeper than .015" or the plate is crackedor damaged in some other way, it should berejected.

c. Examine the gears. If excessive wearis visible on the journals, sides or faces of thegears, or at the point where the drive gear shaftrotates in the lip seal, reject them. If splines areexcessively worn, replace the drive gear.

d. Examine the thrust plates. T h e yshould not show excessive wear on the bronzeside. If deep curved wear marks are visible,replace the plate with new ones.

e. Shaft seals should be replaced. All o-ring seals and backup rings or strips should bereplaced with new.

f. Bearing l.D.'s should have a gray coat-ing. If bronze can be seen shining through theteflon on the suction side, the bearings andplate they are in, should be replaced.

5. Assembly.

a. Install o-ring (12) in rear cover (3).Spread a light film of heavy grease on the o-ring to hold it in position.

b. If gear housing (4) has been replaced,press guide dowels (18 and 19) into replace-ment gear housing. Be certain they are straightand fully seated.

c. Align marks made during disassemblyon gear housing (4) and rear cover (3). Positioncast in recesses on gear housing toward rearcover, then lightly tap gear housing (with Plastichammer) until it contacts o-ring (12).

d. Install backup seal (15) and seal (14)in rear cover (3).

e. Install o-rings (20) in thrust plate (13)then, with trap positioned toward dischargeside of gear housing (4) and bronze side up,slide thrust plate down gear bores on to rearcover (3).


10-11

f. Align tooth and valley marked with lay-out dye then, install drive gear (11) in gear borenearest alignment mark and idler gear (10) inopposite bore.

g. Install o-rings (21) in remaining thrustplate (13).

h. With trap toward discharge side ofgear housing (4) and bronze side down (facinggears) place thrust plate (13) down againstgears.

i. Install o-ring (12), backup seal (15)and seal (14) in front flange (5). Use cleanheavy grease to hold seals and o-ring in posi-tion.

j. Coat splines with clean heavy greaseto protect seal (9).

k. Install front flange assembly (5) withmarks aligned on gear shafts. Slide it downuntil it contacts guide dowels (18).

I. Use plastic hammer to tap front flange(5) onto dowels while checking that seals ando-rings remain in place.

m. Coat threads of capscrews (1) withclean hydraulic oil then install capscrews (1 )and lockwashers (2).

n. Torque capscrews (1 ) to 80 ft. Ibs.(108.48 NM).

o. Check to see if shaft will turn using a12 inch wrench on shaft. It will be tight howev-er, it should turn free with a 15 lb. force onwrench.

6. Installation.

a. Position pump (9, Figure 10-6) onPTO flange and secure with bolts (7) and lock-washers (8).

b. Install elbow (6) and adapter (5).c. Attach hose (4) and secure with

clamps (3).

d. Install straight fitting (2) then connecthydraulic hose (1).

e. Fill hydraulic tank to full mark on levelgauge.

f. Start engine and operate boomthrough its entire range of travel several timesto expel trapped air and to check for leaks.

g. Recheck and top off tank fluid level asspecified in Lubrication Specifications.

BOOM CYLINDER

1. Removal.

a. Park machine on level surface, setparking brake and block wheels.

b. Raise the fifth wheel boom frame tothe top of its travel. Block the boom up in thisposition.

CAUTION

Hydraulic pressure must be relieved prior todisconnecting hydraulic hoses.

c. Provide a suitable container to catchdraining hydraulic fluid then disconnect thehydraulic hose assemblies (1 and 2, Figure 10-11). Dispose of used oil in accordance with fed-eral and local regulations.

d. Attach a suitable sling and hoist to thelift cylinder and take up all slack in the sling.

e. Remove the capscrews (8), and lock-washers (9).

f. Remove the capscrew (11), lockwash-er (12) and cylinder pin (13).


Figure 10-12

1. PIN2. CABLE END3. VALVE SPOOL4. HYDRAULIC HOSE5. HYDRAULIC HOSE6. HYDRAULIC HOSE7. HYDRAULIC HOSE8. HYDRAULIC HOSE9. LOCKNUT10. BOLT11. STRAIGHT FITTING12. 90˚ FITTING13. O-RING14. 90˚ FITTING15. O-RING16. 90˚ FITTING17. 90˚ FITTING18. O-RING19. STRAIGHT FITTING20. O-RING21. CONTROL VALVE22. BRACKET23. COUNTERBALANCE VALVE24. JAM NUT25. MOUNTING SCREWS26. ADJUSTMENT

SLEEVE/RETAINER

Figure 10-11

10-12


10-13

Figure 10-13


I. Lubricate the u-cups and seals withclean hydraulic fluid then, slide the rod assem-bly (19) with all attached parts into the tubeassembly (5).

m. Thread the head (16) into the tubeassembly (5) and tighten with spanner wrenchthen install setscrews (10).

3. Installation.

a. Install the hydraulic boom cylinders,rod end first using the cylinder pins (13, Figure10-11), lockwashers (12) and capscrews (11).

b. Position the lower end of the cylinders(7) over bearing block (10), install capscrews(8) and lockwashers (9).

c. Install the o-rings (4 and 6) andadapters (3 and 5), then connect the hoseassemblies (1 and 2).

d. Service grease fittings (18, Figure 10-13).

e. Start the engine and warm hydraulicoil up to normal operating temperature.Operate the boom through its full range of trav-el 10 times to allow all trapped air to beremoved then check for leaks.

CONTROL VALVE

Removal

1. Park vehicle on level surface, set parkingbrakes, block wheels and shut down engine.

2. Remove the walk-way behind cab to gainaccess to control valve.

3. Tilt cab forward to its maximum height thenengage safety latch.

4. Remove pin from clevis at cab end of cableto disconnect cable from control lever.

g. Remove the boom lift cylinder to aprepared work area.

h. Remove the adapters (3 and 5) and o-rings (4 and 6).

2. Disassembly, Inspection and A s s e m b l y(Figure 10-13).

a. Unscrew the 2 setscrews (10) thenremove head (16) from the tube assembly (5).

b. Withdraw all the components from thetube assembly (5).

d. Clamp the rod assembly (19) end in avise then, remove the self locking nut (6), u-cups (8) and piston (9) from the rod assembly(19).

e. Slide the head (16) from the rodassembly (19) then remove the o-ring (13),backup ring (14), wiper (18) and u-cup (17)from the head (16).

f. If the bushing (12) is to be replaced, itmust be pressed out of the rod assembly (19)and a replacement pressed in.

g. Remove the wear rings (15) only ifinspection reveals excessive wear.

h. Check the inside surface of the tubeassembly for scoring or scratches. Smooth lightscratches with crocus cloth. Replace tubeassembly if excessively worm.

i. Check the sliding surfaces of the piston(9) and rod assembly (19). Smooth fine scratch-es with crocus cloth. Replace parts foundexcessively worn.

j. Install seal kit which includes the u-cups (8 and 17), o-rings (7 and 13) and wiper(18).

k. Assemble the head (16), piston (9)and o-ring (7) onto the rod assembly (19) thensecure with self locking nut (6).

10-14


10-15

SYMPTOM

Hydraulic pump exces-sively noisy but lifts

Oil hot

Lift sluggish

5th wheel boom leaksdown

Lift cylinder leaks exter-nally

Pump leaking at shaft

SUGGESTED CAUSE

Low oil

Suction filter restricted

Suction line restricted or col-lapsed.

Change to proper viscosity oil.

Low oil

Relief valve malfunction.

Machine overloaded

Change to proper viscosity oil.

Low oil.

Relief valve malfunction.

Pump worn out

Cylinder piston packing leaking

Cylinder piston packing leaking

Control lever not centering valvespool

Control valve leaking internally.

Damaged or worn rod seal andwiper

Worn or damaged shaft seal

Worn or damaged bearings

SUGGESTED REMEDY

Fill reservoir with proper oil tospecified level.

Clean or replace suction filter

Install new suction line.

Oil too heavy.


Clean, adjust, replace relief valve.

Remove overload from machine

Oil too light


Clean, adjust or replace reliefvalve

Inspect, repair or replace

Rebuild or replace cylinder


Broken centering spring stickingvalve spool, cable or lever

Replace control valve


Replace seal or pump

Replace pump

Hydraulic System Troubleshooting


10-16

SYMPTOM

Oil foamy

SUGGESTED CAUSE

Suction leak between reservoirand pump

Low oil

Wrong oil

SUGGESTED REMEDY

Inspect and tighten all connections - replacing any defectivepads.


Drain and refill with proper oil tospecified level.

Hydraulic System Troubleshooting (Cont.)

CAPACITY BOOM & FIFTH WHEEL

TOPIC 11 – Fifth Wheel System

Terminal Objective:

Upon completion of this unit, the student will be knowledgeable in the Fifth WheelSystem and its operation which is found on Capacity spotters.


• Understand specific topics such as highway lock feature, air cylinder releaseand lock jaw inspection.

• Perform Fifth Wheel diagnostics and troubleshooting

11-1


11-2

DESCRIPTION

The TJ5000 utilizes a 36 inch (91.44 cm) diam-eter fifth wheel set up to couple 2 inch (5.08 cm)diameter trailer king pins. An in-cab air operat-ed unlatch control is supplied. Relatch is auto-matic.

Servicing

Servicing the fifth wheel consists of lubricatingthe pivot shaft and the fifth wheel surface platewith multipurpose grease. There are no adjust-ments on the fifth wheel plate.

Periodic Inspection and Test

Perform the following procedures to check thejaw release air cylinder Figure 12-1) for service-ability:

a. Have operator in cab depress releasebutton and hold.

b. Apply a solution of soapy water to therelease cylinder shaft seal area to determine ifleaks exist.

c. Allow release button to return to outposition then disconnect the air hose from therelease cylinder.

d. Remove air cylinder from fifth wheel.

e. Collapse and extend cylinder to checkstroke for binding. Replace cylinders that bind.

f. Reinstall cylinder on fifth wheel andconnect air hose.

CAUTION: Do not overtightencylinder mount bolts. Cylinder shouldswing freely on either mount.

g. Use appropriate tool to push forwardon locking jaws until they lock.

h. Be certain air system is pressurizedup to 80-120 PSI, then have operator in cabdepress and hold release button. Jaws shouldseparate and allow for total jaw opening.

Repair

The following paragraphs describe the replace-ment of various components of the fifth wheeland boom assembly. The components may beremoved individually, so perform only thosesteps necessary to effect the desired repair.Refer to the figures as indicated for locationand identification of parts while performingthese procedures.

Fifth Wheel (Holland) - Removal

NOTE

All serviceable parts of the fifth wheel may beremoved without removing the entire fifthwheel.

Figure 12-1


a. Park machine on level ground, setparking brake and block wheels to preventmovement.

b. Raise boom approximately six inchesto increase access to underside of fifth wheel.

c. Shut down engine then bleed brakeair pressure to zero pressure by depressingand releasing brake pedal approximately 30times.

d. Refer to Figure 12-1 and disconnectair hose (1) from elbow (2).

e. Attach suitable hoist and sling to fifthwheel (3) then, drive out roll pins (4) and brack-et pins (5). Hoist fifth wheel (3) clean to pre-pared work area.

2. Disassembly.

a. Refer to Figure 12-2 and remove cot-ter pins (6) and lock pins (7) then slide out locks(8) with spring (9).

NOTE

Locks (8) are sold as a matched set.

b. Remove locknuts (10) and bolts (11)and remove air cylinder (12). Remove elbows(2 and 13) and air filter (14) from air cylinder..

c. To remove cam (15), remove bolt (16),washer (17), roller (18), washer (19) thenremove locknut (20) and washer (21).

d. Lift cam (15) and spring rod (24) outtogether. Be certain to retain roller (22), bolt(27), washers (23 and 25) and spring (26).

e. Slide yoke (28) and spring (29) out offifth wheel (3) through opening left by locks (8).

f. Drive out roll pin (30) to release sec-ondary lock (31) and spring (32). Leave sec-ondary lock handle (33) installed.

3. Cleaning, Inspection and Repair.

a. Clean all metal parts except air cylin-der (12) in solvent and dry with compressed air.

b. Check the locks (8) and lock pins (7)for cracks and excessive wear. Replace locksas a set if found unserviceable.

c. Check cam (15), rollers (18 and 22),yoke (28) and secondary lock (31) for exces-sive wear, cracks or damage. Replace partsfound unserviceable.

d. Check all springs (9, 26, 29 and 32)for cracks, fatigue or excessive wear. Replacesprings if found unserviceable.

e. Check bracket pins (5) for cracks andexcessive wear. Replace worn pins.

f. Inspect fifth wheel plate (3) for cracks,wear or damage of any variety. Replacecracked or excessively worn fifth wheel plate.

g. Check rubber bushings (34) for cracksor signs of deterioration. Replace bushingsfound unserviceable.

4. Assembly and Installation.

a. Obtain the necessary replacementparts and assemble fifth wheel as follows:

b. Attach secondary lock (31) to second-ary lock handle (33).

c. Position spring (32) and secondarylock (31) within fifth wheel (3) and secure withroll pin (30).

d. Assemble spring (29) onto yoke (28)then install them in fifth wheel (3).

e. Assemble spring rod (24) to cam (15)then install washer (25), spring (26) and wash-er (25).

f. Insert free end of spring rod (24)

11-3


through tab on fifth wheel (3) and position cam(15) over yoke (28).

g. Secure cam (15) to yoke (28) withwasher (19), roller (18), washer (17) and bolt(16).

h. Secure cam (15) to fifth wheel (3) with

washer (23), roller (22), washer (21) and bolt(20).

i. Assemble locks (8) and spring (9) thenslide the assembly into the fifth wheel (3) untilholes for lock pins (7) align.

j. Install lock pins (7) and cotter pins (6).

Figure 12-2

11-4


11-5

k. Assemble air filter (14), air cylinder(12), street elbow (13) and elbow (2) theninstall cylinder assembly on cam (15) and fifthwheel using bolts (11) and locknuts (10).

I. Install rubber bushings (34).

m. Attach suitable hoist and sling to fifthwheel assembly and maneuver it into positionon boom assembly.

n. Install bracket pins (5) and roll pins(4).

o. Connect air hose (1) to elbow (2).

p. Start engine and allow air systempressure to build to normal operating pressure.Test operation of fifth wheel release cylinder.

q. Check air hose connections for leaksusing soapy water solution.

r. Service the fifth wheel with lubricant asshown in Lubrication Chart of this manual.

Boom - Removal

NOTE

The boom may be removed with the fifth wheelinstalled however, removing the fifth wheel willease handling the boom.

a. Refer to the preceding paragraph andperform fifth wheel removal procedures or if thefifth wheel is to be left attached, refer to figure15-1 and disconnect air line (1) from elbow (2).

b. Refer to figure 10-3 and remove bolts(1), lockwashers (2) and boom step (3).

c. Remove bolts (4) and lockwashers (5)to allow removal of boom cylinder pins (6).NOTE

Once boom has been removed, allow boomcylinders to lean back and rest against driveaxle.

d. Attach a suitable hoist and sling toboom (8) then exert a lifting force sufficient tosupport weight of boom.

e. Release any clamps securing releasecylinder air hose cylinder to boom.

f. Remove locknuts (9) and bolts (10).

g. Support spacer (12) then, drive outboom pivot pin (11).

h. Hoist boom (8) clear of machine.

i. Check bushings (13) for wear. Pressworn bushings out.

2. Inspection.

a. Check all welds for cracks and haveany cracks rewelded.

b. Check cylinder pins (6) for excessivewear. Replace pins found unserviceable.

3. Installation.

a. Align grease hole in bushings (13)with grease fittings (14) then press bushingsinto position.

b. Hoist boom (8) into position on vehicleframe and install boom pivot pin (11) and spac-er (12). Secure with bolts (10) and locknuts (9).

c. Move boom cylinders into positionthen install cylinder pins (6), bolts (4) and lock-washers (5).

d. Connect air hose for release cylinderto boom with clamps.

e. Install boom step (3) with bolts (1) and


11-6

lockwashers (2).

f. Refer to the preceding paragraph andperform fifth wheel installation procedures.

g. Service all grease fittings (7 and 14).

h. Start engine and test operation ofboom and fifth wheel before returning machineto service.

Figure 12-3


Trailer Upper Coupler orBolster Plates

The inspection of the trailer upper coupler orbolster plate and kingpin is just as important asthe inspection of its mating component, the fifthwheel.

This inspection should be conducted everythree months or 30,000 miles.

This inspection, based on SAE J700 Jun 85should include the following:

1. Check the flatness of the upper coupler orbolster plate:

Use a 48” straight edge. Any bumps, valleys orwarping will result in uneven loading, a crackedfifth wheel, poor lubricant retention, galling ofthe fifth wheel and trailer upper coupler andpoor lock life. (See illustration below)

The bolster plate should be replaced if it isdeformed more than is shown in the illustration.

2. Inspect the kingpin:

Using a Holland kingpin gage (p/n TF-0110)inspect for the following:

A. Bent kingpin:A bent kingpin can result from excessive cou-

pling speed or impacting the trailer into a dock.In addition to being bent, the kingpin may bepulled down in the center deforming the bolsterplate. If this condition exists, the kingpin shouldbe replaced.

B. Kingpin length:The kingpin must be of the proper length tocouple properly with a fifth wheel. Additionally,if a lube plate is used in your operation, thekingpin must be sized to compensate for thethickness of the lube plate to maintain theseproper dimensions.

Long kingpin:A long kingpin will result in excessive wear inthe locks and coupling difficulty. If this condi-tion exists, the kingpin should be replaced.

Short kingpin:A short kingpin will accelerate lock wear andmay interfere with proper fifth wheel coupling.If this condition exists, the kingpin should bereplaced.

C. Worn kingpin:If the kingpin is worn 1/8” or more on either the2” or 2-7/8” diameter in either direction asshown in this illustration, the kingpin should bereplaced.

11-7


PROBLEM POSSIBLE CAUSE CORRECTIVE ACTION

Fifth wheel doesn’t raise 1. Low fluid level. 1. Check reservoir and raise.service as required.

2. Broken hose or loose 2. Examine all hoses and fitting.fittings and look for leaks. Replace damaged components,

tighten loose fittings.

3. Insufficient oil pressure.

3a. Check operation of controlvalve and control linkage. Adjustas needed.

3b. Check output from pump forflow and pressure.

3c. Check pump to PTOmounting.

3d. Check all hoses forrestrictions.Free hoses of restrictions.

4. Cylinder piston packing 4. Install seal kit in cylinderworn or leaking.

TROUBLESHOOTING

11-8

CAPACITY CAB LIFT SYSTEM

TOPIC 12 – Cab Lift System

Terminal Objective:

Upon completion of this unit, the student will be knowledgeable in the cab hydraulicsystem and its operation which is found on Capacity spotters.


• Identify schematics and location of components• Understand specific functions of latches, lift pump and cylinder• Perform Hydraulic System diagnostics and troubleshooting

12-1


12-2

DESCRIPTION

The cab tilt system provides a means to tilt thecab forward for easy access to the engine,transmission and hydraulics. Hydraulic fluid ispumped to the cab lift cylinder (Figure 15-1) bya self contained electric/hydraulic pump andreservoir (1). Moving the lever clockwise caus-es a valve to open allowing hydraulic fluid toreturn to the pump reservoir.

Servicing

Servicing the cab lift system consists of main-taining the fluid level in the pump reservoir andperiodic inspections of the hoses, lines, fittingsand hydraulic cylinder for leaks. The safety lockbar should also be inspected for cracks, brokenteeth and freedom of movement. Refer toSection 1 for the type of oil to be used in thecab tilt system.

Checking Fluid Level

a. Lower cab to fully down position.

b. Remove cap (5, figure 15-1) and check level.

c. Add specified oil as necessary to maintainreservoir (1) full.

d. Reinstall cap (5).

Figure 15-1


12-3

b. Raise cab to the limit of its travel thenallow it to settle back until it engages the firstnotch in the safety lock bar. (10, Figure 15-4).

c. Disconnect hydraulic hose (6) fromfitting (7).

d. Drive out roll pin (5) then removecylinder pin (4) and spacer (6).

e. Remove locknut (2) and bolt (3) torelease cylinder (1).

Cab Tilt System Repair

The following paragraphs outline the proce-dures for removal, repair and replacement ofcomponents of the cab and cab tilt system. Thecomponents may be removed and servicedindividually. Perform only those steps neces-sary to effect the desired repairs. Refer to thefigures as indicated for location and identifica-tion of parts while performing these procedures.

Cab Tilt Cylinder

1. Removal

a. Park machine on level surface, setparking brake, block wheels and shut downengine.


12-4

Disassembly

a. Refer to Figure 15-5 and using aspanner wrench rotate stuffing box to removeretaining ring (10) from tube assembly (1)through milled slop in tube.

1. TUBE ASSEMBLY2. LOCKNUT3. O-RING4. BACK-UP RING5. PISTON6. PISTON SEAL (2 PIECE)7. ROD ASSEMBLY8. WIPER9. ROD U-CUP10. RETAINING RING11. STUFFING BOX12. STUFFING BOX O-RING13. BREATHER14. 90˚ FITTING15. STUFFING BOX BACK-UP

b. Withdraw rod assembly (7) from tubeassembly (1) with all attached parts.

NOTE: Do not clamp on chrome rod surface.

c.locknut (2), piston (5), stuffing box (11)and snap ring (10) from rod assembly (7).

d. Remove stuffing g box o-ring (12),rod u-cup (9) and wiper (8) from stuffing box(11).

e. Remove backup rings (4), piston seal(6) and rod o-ring (3) from piston (5).

f. Discard all seals, o-rings and wiper.

g. Remove breather (13).

3. Inspection and Repair

a. Clean all metal parts in solvent andair dry.

b. Check inside of tube assembly (1)and stuffing box (11) for scratches, scoring andexcessive wear. Check tube ID at mill slot forburrs and remove any present. Repair lightscratches with crocus cloth. Replace partsfound unserviceable.

c. Check bearing surfaces of piston (5)and rod assembly (7) for scratches with crocuscloth. Replace parts found unserviceable.

4. Assembly and installation.

a. Obtain the necessary replacementparts.

b. Lubricate all seals, o-rings and wiperwith fresh hydraulic fluid prior to assembly.

c. Assemble rod u-cup (9), wiper (8) andstuffing box o-ring (12) on stuffing box (11) andbackup (15).

Figure 15-5

CLAMP HERE

MILL SLOT CLAMP HERE


12-5

d. Lubricate rod assembly and installstuffing g box assembly onto rod.

e. Assemble piston seal (6), back-uprings (4) and rod o-ring (3) on piston (5).

f. Install piston assembly and locknut (2)on rod assembly and torque to 175-200 ft. lbs.

g. Lubricate piston assembly then slideit into tube assembly (1).

h. Slide stuffing box assembly into tubeassembly then align hold in mill slot. Installretaining ring (10). Spin head to pull retainingring fully into cylinder.

i. Install breather hand tight. Excessivetightening may damage breather.

j. Compress cylinder to its fully col-lapsed condition then, position cylinder in placeunder cab and install bolt (3) and locknut (2) tosecure bottom end of cylinder.

k. Connect hydraulic hose (8) to fitting(7) and pump cylinder full of hydraulic fluid toextend cylinder out to cab mount.

l. Install cylinder pin (4), spacer (6) androll pin (5) to secure upper end of cylinder.

m. Raise and lower cab several times toexpel trapped air and check hose connectionsand stuffing box for leaks.

n. With cab fully lowered check oil levelin reservoir and add as necessary to bring toFULL.


12-6

INTRODUCTION

Cab Cushion Air Cap Suspension Systems aredesigned to protect the cab and driver from thevibrations of on and off road use. Follow thesesimple maintenance guidelines and routinevisual inspections to assure proper operation:

ALIGNMENT: Visually checking that the shockabsorber is centered radially within the restrain-ing cylinder is critical to obtain maximum life ofyou Cab Cushion. Alignment should be viewedfrom each side of the tractor and from the rear.If misaligned, tilt the cab and loosen the boltsholding the can weldment to the cab. Removethe lower cap screw holding the linkagebetween the leveling valve and the catch weld-ment. Push the leveling valve arm up to fill theair bags with air until flow stops. This forces theshock in alignment while the cab is tilted.Lower the cab slowly. The can weldmentshould be forced into alignment with the shock(you may have to tap the can weldment intoplace). Set ride height to 1.75” and visuallycheck alignment, tighten can weldment boltsand re-attach leveling valve linkage.

RIDE HEIGHT: Check the ride height of eachside by measuring the distance from the bottomof the can weldment to the top surface of thecatch weldment. If it doesn’t measure 1.75” +/-.13”, then adjust by following the steps below:

a. Make sure vehicle air system contains aminimum of 100 PSI of air.b. Loosen both 1/4-20NC nuts that mount HCVto suspension approximately 1/2 turn.c. Rotate height control valve to set proper rideheight of 1.75” +/- .13”.d. Tighten both 1/4-20NC nuts to 66 in.. lbs.e. Recheck ride height.

LEVELING VALVE OPERATION

Check the leveling valve by pulling down andholding on the cab handle and counting howmany seconds it takes for the air bags to raisethe cab to ride height. If it takes longer than 10seconds or less than 2 seconds, the valve maybe broken or the filter is clogged and the entirevalve needs to be replaced.

Remember, your air tanks should be purged atleast once daily to prevent premature failure ofthe valve.

Cab Cushion Service Instructions

AIR BAG

A leaking air bag could be caused by misalign-ment or operating on low pressure. If an airbag needs to be replaced, close the air supplyvalve to the suspension, tilt and lock the cab,remove the pipe fitting and simply lower thebag/shock assembly from the restraining cylin-der after removing the two 7/16 flange nuts atthe top.

Remove the two snap rings (16) and drive outthe pin (15) that holds the shock (14 or 19)inside of the air bag (2 or 18). Pull out andinspect the shock for damage or leaking oil.Replace the shock and air bag in reverse orderof removal. Make sure to grease o-ring loca-tions on air bag and at pin, then extend shockbefore installation. A soap water solution maybe applied to inside edge of air bag to easeinstallation. Torque top flange nuts to 28-34 ft.lbs.

1.75” +/- .13”AT RIDEHEIGHT


SHOCK ABSORBER

The shock absorber may need to be replaced ifthe suspension has been operated for a periodof time with a blown air bag, on low pressure, orafter a few years of service. Follow the stepsabove for removal from air bag. Remove thecatch weldment component (4 or 20). Reinstallin the reverse order.

TILTING DAMAGE

Follow the steps only if absolutely necessary.Disassembling the latch will void the warrantyon the latch. The hydraulic rotary latch is notfield serviceable. If operational problemsoccur, replace entire unit. The latch, catchweldment and shock absorber could be dam-aged if the latch fails to disengage before thecab is tilted. This will happen if the pump is notworking and the cab is tilted by another means.To disengage the latches, remove the stop cap(5) and pin (8) to allow the plunger (3) to retractwhich disengages the catch weldment from thehook. Always check that the latch indicator pinis below the surface to assure that it isengaged.

HYDRAULIC ROTARY LATCH ASSEMBLY

NOTE: The hydraulic rotary latch is not field

serviceable. If operational problems occur,replace entire unit.

Left Hand Air Bag

Right Hand Air Bag

12-7


CONDITION

Tilt cylinder will not retractor advance

Pump handle kicks up

Pump functions only onlast portion of stroke

Pump will not build pres-sure

Pump leaks between pumpbase and reservoir

Cab latch inoperable

POSSIBLE CAUSE

Damaged or broke line.

Pressure builds up in both direc-tions, due to plugged orifice inthe pump.

Oil reservoir not filled on pump.

Worn or faulty seal in cylinder.

Crossed hoses

Outlet ball leaking

Reservoir low on oil

Inlet ball leaking

Dirt on inlet screen

Reservoir empty or low

Inlet ball leaking

Bad o-ring on selector valvespool

Relief valve improperly set orblocked open

Bad o-ring on reservoir

Damaged or broken hydraulichose

Binding piston

CORRECTION

Replace hydraulic hose

Replace pump

Fill pump reservoir

Replace cylinder and/or replaceseals.

Replumb and bleed

Replace or rebuild pump

Fill reservoir

Replace pump

Clean screen and reservoir

Fill reservoir





Replace hose

Replace latch

Troubleshooting Cab Lift Pump

Unsatisfactory operation of the tilt system could be caused by a malfunction of the pump assem-bly, tilt cylinders, or latch, or by restricted or damaged hydraulic lines. The Troubleshooting Tablebelow outlines typical conditions, possible causes, and corrections. Check flow through each com-ponent, such as fittings. Evaluate before replacing component.

12-8

CAPACITY CAB LIFT SYSTEMPOSSIBLE CAUSE

Plugged orifice in pump

Cab latch binding. Fails tounlatch

Pump does not build pressure

Check for other causes above

Reservoir overfilled.

Damaged seal

Reservoir low or empty

Inlet ball leaking

Relief valve improperly set orblocked open

Air pump poppet stem stuck

Bad seal on large air piston

Push button ball will not unseat

Low inlet air pressure

Bad seal on poppet stem

Bad o-ring on poppet stem

Bad o-ring on air inlet swivel

Bad seal on main air pump pis-ton

Bad seat in push button

Bad o-ring on push button stem

Bad o--ring on air valve body

CONDITION

Cab stops moving when infree-fall

Cab fails to tilt

Hydraulic fluid forced outof breather

Oil leak at hand pumpplunger

No flow with air pump run-ning

Air pump will not pump

Air leak, air pump will notrun

Air pump will not stop run-ning

Air leak at push button

CORRECTION

Replace pump

Replace cab latch cylinder

Replace pump

Take appropriate corrective action

Drain oil out and properly fill

Rebuild or replace pump

Fill reservoir

Check ball and seat for chips,clean and reseat ball to seat

Replace relief valve assembly

Replace air motor assembly


Replace air button assembly

Increase air supply



Replace air inlet assembly





12-9

front axle & steering

Documents