jacobs brake caterpillar c10 & c12 installation instructions 021222b

8/3/2019 Jacobs Brake Caterpillar C10 & C12 Installation Instructions 021222B

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For C aterp illa r C -1 0 and C -12 E ng ines

The Jake Brake' Model 31OAis designed and approved for use on all 1996 and later Caterpillar C-10engines with an engine serial number prefix of 2PN. The Jake Brake" Model 312A is designed andapproved for use on all 1996 and later Caterpillar C-12 engines with an engine serial number prefixof 1YN.Jacobs Service letters should be consulted for addit ional applications and updated information.Information in this manual was current at the time of printing and is subject to change without noticeor liability.


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Table of ContentsSec tion 1 : In tr oduc tion 3Housing Identification 3Engine Identification 3Tools Needed 3Recommended Torque Values 3

S ec tio n 2 : E n g in e P re p ar at io n 4 - 6Valve Cover Base 4Exhaust Valve Bridge Replacement 4Brake Housing Mounting Stud Installation 5Valve and Injector Adjustments 6Exhaust Valve Clearance Adjustment 6

S ec ti on 3 : B ra ke Hous in g In s ta ll at io n 7 - 8Housing Installation 7Slave Piston Adjustment 7Spacer Installation 8

S ec tio n 4 : E n gin e B ra ke O pe ra tio n C he ck 9Bleed Engine Brake Housings 9Rocker Cover Installation 9Chassis Wiring 9

S ec ti on 5 : E n g in e B ra ke Ma in te n an c e 10 - 17Theory of Operation 10Engine Brake Overhaul Procedures 11Solenoid Valve 12Control Valve 13Accumulator 14Slave Piston Adjusting Screw (D-Lashj 14Master Piston 15Slave Piston 16Screw and Pin Assembly Replacement Procedure 17

Safety PrecautionsThe following symbols in this manual signal potentiallydangerous conditions to the mechanic or equipment Readthis manual carefully. Know when these conditions canexist Then, take necessary steps to protect personnel aswell as equipment.

THIS SYM BO L W AR NS O F PO SSIBLEP ER SON AL I NJ UR Y.

16cAUTION ITH IS S YM BO L R EFE RS T O P OS SIBLEE QU IP ME NT D AM AG E.

NOTE:IN DICATES AN O PERATIO N, PRO CED UR E O RIN STRU CTIO N TH AT IS IM PO RTANT FO RCORR EC T S ER VIC E .

Fuels, electrical equipment, exhaust gases and movingengine parts present potential hazards that could result inpersonal injury. Take care when install ing an engine brake.Always use correct tools and proper procedures as outlinedin this manual.

SEE JAC OBS DR IVER 'S M AN UAL FO R PR OPERE NG IN E B RA KE D RIV ER T EC HN IQ UE S.TH E JAKE BR AKE RETARDER IS A VEHICLESLO WIN G DEVICE , NO T A VEH ICLE STO PPIN GDEVICE . IT IS N OT A SUBSTITU TE FO R THES ER VIC E B RA KIN G S YS TE M. T HE V EH IC LE 'SSERVICE BRAKES MUST BE USED TO BRINGTHE VEHICLE TO A COM PLETE STOP.

2 IN STALLATIO N M ANU AL FO R M ODELS 310N312A


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Section 1: IntroductionHousing IdentificationThe housing serial number, engine brake model numberand housing part number are printed on a nameplatelocated on the top surface of the housing.

FIG. 1

Engine IdentificationEngine serial number information is printed on thenameplate located on the intake manifold or stamped onthe lower right side of the block. Engine serial numberprefix U2PN"designates a 1996 or later model year C-l 0engine. Serial number pref ix "1YN" designates a 1996 orlater model year C-12 engine.

Tools NeededThere are no special tools required for installation of theModels 3 1OAand 312A Jake Brake" engine retarders.However, the Caterpil lar Series C-l 0 and C-12 engines andModels 31OA and 312A Jake Brake retarders are of metricdesign and will require the use of metric hand tools.

Recommended TorqueValuesCylinder head bolt (see section on Brake Housing

Mounting Stud Installation, page 5)Cylinder head bolt spacer 95 15 Nom (70 11 Ib.-ft.)

95 15 Nom (70 11 Ib.-ft.)80 15 Nom (59 11 lb.-ft.)55 10 Nom (41 7 Ib.-ft.)

Brake mounting stud assy.Housing hold-down nutHousing hold-down bolt(lOx 70 mm)

Spacer/valve cover bolt(6 x 100mm)

12 3 Nom (9 2Ib.-f t.)

Slave piston adjusting screwlocknut 35 8 Nom (25 6 lb.-ft.)

Exhaust and inlet rocker armadjusting screw locknut 25 7 Nom (18 5Ib.-ft.)

Solenoid valveValve with 12-point, 7/8" headValve with 6-point, 3/4" head

12.5 Nom (110 lb.-in.)20 Nom (180 lb.-in.)

NOTE :U NLE SS O TH ER WIS E S PE CIF IE D, T HE T OR QU EVALUES L ISTED HERE AND IN THE TEXT ARED IRECT VALUES USING NO TO RQUE W RENCHAD APTE RS O R EXTE NS IO NS. W HEN AD AP TE RSO R EXTENSIONS ARE USED W ITH A TO RQUEW RENCH , THE TORQUE VALUES MUST BEA DJ US TE D. F OL LOW T HE M AN UF AC TU RE R'SRECO MM ENDED PROCEDURES FO R THETO RQUE W RENCH AND ADAPTER BE INGUSED .

IN STALLAT IO N M AN UA L FO R M OD ELS 31 O A/312A 3


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Section 2: Engine PreparationValve Cover BaseThe illustrations in this manual show the valve cover base inplace during engine brake installation. Production engineswill be equipped with a cover base (1) that includes threesupport brackets (2) for containment of the injector wireharnesses (see Fig. 2).The support brackets may prevent access to the threecylinder head bolts which must be removed for theinstallation of three Jacobs bolts. Because the injectorharness support brackets are diff icult to remove with thecover base in place, it may be necessary to remove thevalve cover base to permit access to the cylinder headbolts.Exhaust Valve BridgeReplacementThoroughly clean the engine.Remove all accessory equipment that is necessary toremove the rocker covers.Remove the rocker covers. Note the valve arrangementshown in Fig. 3.Refer to Fig.4. Loosen the locknut (2) and the adjustingscrew (1) on the exhaust rocker arm (3).Move the exhaust valve push rod aside to permit the rockerarm to be rotated.Remove the Caterpil lar standard exhaust valve bridge (1)(see Fig.5).Install the Caterpillar bridge assembly used for Jacobs'screw and pin assembly (2) (see Fig. 5) with the adjustingscrew toward the rocker shaft as shown in Fig. 6. This is1800 from the original position.Lubricate the Jacobs' bridge, top pad and screw and pinassembly with clean lube oil.

16CAUTION IDO NO T D IS AS SEMBL E T HE J ACO BS ' B RIDG EA SS EMBL Y A S T HIS W IL L C H ANG E T HEPOSIT ION OF THE LEVE L ING SCREW .IM P RO PE R L EV EL ING O F T HE BRIDG E CO ULDRESULT I N SERIOUS ENG INE DAMAGE .

F IG . 2

EXH AU ST VALVES o I NTA KE VA LVESFIG. :3

FIG . 4

F IG . 5

4 IN S TA LL AT IO N MANUA L F OR MODE LS 3 10 N3 12 A


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E XHAUST V AL VEBRIDGE

F IG . 6

C DFIG.7

F IG . 8

TYPE 115.7:3 mm (0.619") DIAMETER< D @ ) ) ) ) ) ) ) ) ) ) ) ) ) )

~~------~]~'~I~ITYPE 214.58 mm (0.574") DIAMETER

F IG . 9

I &CAUTION IBE SURE THE EXHAUST VALVE BR IDG E ISPR OPER LY LO CA TE D O N THE EXH AUS T V ALV ESTEM . THE VALVE STEM MUST F IT IN THECOUNTERBORE OF THE BRIDGE ON THE S IDEW ITH OU T TH E AD JU ST IN G SC REW . FA ILU RETO DO SO W ILL RESULT IN SER IOUS ENG INEDAMAGE .

Brake Housing MountingStud InstallationRefer to Fig.7 to identify the cylinder head bolts (1) androcker shaft hold-down bolts (2) to be replaced.

I &CAUTION IR EPLAC E TH E TH REE C YL IN DER H EA D BO LTSW ITH THE JACOBS BOLTS ONE AT A T IME .TH IS W ILL PR EV EN T C YLIN DER H EADDISTORTION.

Remove the cylinder head bolt and washer closest to theintake manifold, one per brake housing.Using a blow gun nozzle with an extension, remove the oilfrom the cylinder head bolt hole.

W EAR EYE PROTECT IO N AND COVER THECYLINDER HEAD BOLT HOLE W ITH TOW ELSTO M IN IM IZE O IL SPRAY AND HELP PREVENTP ER SO N AL IN JU RY .

Refer to Fig.8. Install the Caterpillar washer (1) on theJacobs cylinder head bolt stud (2). Coat the head boltthreads (2) and both faces at the washer (1) with threadlubricant (Caterpillar 6V4876 Molylcote Paste lubricant orequivalent) prior to assembly. Install the bolt and torqueaccording to the following procedure.Two cylinder head bolt configurations have been used onthe C-10 and C-12 engines. Early engines used a ful l shankbolt (Type 1, Fig.9). later engines used a reduced shankbolt (Type 2). When installing a Jake Brake" kit, use thefollowing torque procedure.T yp e 1 (F ull S ha nk) T orqu e P ro ce du re1. Torque the bolt to 150 15 Nom (110 11 lb.-ft.).2. Tighten the bolt an additional 90 5 degrees.

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T yp e 2 (R ed uce d S ha nk ) T orq ue P ro ce dure1. Torque the bolt to 160 15 Nom (120 11 lb.-ft.).2. Tighten the bolt an additional 90 5 degrees.When reinstalling a Jake Brake retarder following cylinderhead replacement, follow the Caterpil lar cylinder headtorquing procedure. Make note of what type of bolt is ineach location to ensure it is torqued to the correct value.Repeat the above procedure, one bolt at a time, for theremaining two cylinder head bolts.Install the cyl inder head bolt spacers (3, Fig. 8) on thecylinder head bolt studs (2) and torque to 95 15 Nom(70 11 lb.-ft.).Remove the rocker shaft hold-down bolts from the sixlocations next to the exhaust rocker arms (2, Fig. 7).Install the brake mounting stud assemblies (2, Fig. 10) andtorque to 95 15 Nom (70 11 lb.-ft.).Valve and InjectorAdjustments

NOTE :E XH AU ST V ALV E C lEA RA NC E AD JU ST MEN T ISR EQ UIR ED . A DJU STM EN TS O F TH E IN TAK EV ALV E C lEA RA NC E AN D T HE IN JEC TO RS W illBE REQ UIRED O NLY ACC OR DING TO VEH ICLEM ilE AG E O R E NG IN E S ER VIC E IN TE RV AL S.

Refer to Caterpillar service literature for proper exhaustvalve, intake valve and injector clearances.Make al l adjustments with the engine stopped and cold.Follow the sequence in the following table:

Se t In take Set Exhaus t SetS e t E n g in e Va lve No . Va lve No . In jecto rCyl. #1 TOC 1,2,4 1,3,5 3,5,6CompressionCyl.#6 TOC 3,5,6 2,4,6 1,2,4Compression

Exhaust Valve ClearanceAdjustmentRefer to Fig. 11. locate the exhaust rocker arm adjust ingscrew in the socket of the exhaust valve push rod (1). Insertthe feeler gage between the rocker arm and valve bridge.Turn the rocker arm adjusting screw (2) clockwise until theproper clearance (4) is set Hold the adjusting screw andtorque the locknut (3) to 25 7 Nom (18 5 lb.-ft.).

F IG . 1 0

F IG . 1 1

6 IN ST AL LA TIO N M AN UA L F OR M OD ELS 31 0A /3 12 A


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Section 3: Brake Housing InstallationHousing InstallationPosition the engine brake housings on the mounting studnuts and align the slave piston foot squarely over the bridgescrew and pin assembly. Install the Jacobs hold-down nuts(1) on the brake mounting studs and torque to 80 15 Nom (59 11 lb.-ft.) (see Fig. 12).Refer to Fig. 12. Install the 70 mm bolts (2) through thehousing into the spacer (one per housing) and torque to55 10 Nom (41 7Ib.-ft .).Be sure the slave piston foot (1) remained aligned squarelyover the bridge screw and pin assembly (2) duringtorquing. This will insure proper activation of the exhaustvalve stem. Reposition the housing if necessary (seeFig. 13).

Slave Piston AdjustmentS la ve P is to n Ad ju stmen t S equence

Set EngineCyl. #1 TOCCompression

Set SlavePiston No.1,3,5

Cyl. #6 ro cCompression

2,4,6

S la ve P is to n C le a ra nce Set tin gEngine SIN Prefix Gage PINlearanceC-10C-12

0.64 mm (0.025'') 0220451.14 mm (0.045'') 016896

2PNlY N

Refer to Fig. 14. With the exhaust valves closed on thecylinder to be adjusted, insert the proper Jacobs feeler gage(2) between the slave piston and the actuating pin (3) inthe valve bridge adjusting screw.Turn the slave piston adjusting screw (1) in until a slightdrag is felt on the feeler gage.

Hold the adjusting screw in this position and tighten thelocknut to 35 8 Nom (25 6 lb.-ft.).Rotate the engine 3600 and set the clearance on theremaining slave pistons.

FIG. 12

FIG. 13

FIG. 14

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Spacer Installation.5 mm GAP(0.:375")

FIG . 15

W IT HOU T HOU SIN G

W IT H HOU SIN G

FIG . 16

F IG . 17

Be sure the seal is seated in the groove in the bottomsurface of the Jacobs' spacer (see Fig. 15).

NOTE:A 9.5 MM (0.375") GAP SHOULD BE LEFTBETW EEN EACH END OF THE GASKET ANDT HE S PA C ER .

Connect both solenoid lead wires (1) to the terminal leadouts (2) on the solenoids (see Fig. 16).

NOTE:THE SOLENO ID LEAD W IRES ARE NOTPO LAR ITY SEN SIT IVE AND M AY BEC ON NE CT ED IN E ITH ER D IR EC TIO N.

lnstall the three Jacobs' spacers on the valve cover base(see Fig. 17, only 2 shown for clarity).

INSTALLATION M AN UAL FO R M OD ELS 310N312A


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Section 4: Engine Brake Operation Check

FIG.18

FIG. 19

Bleed Brake Housings

W EAR EYE PROTECT ION AND DO NOTEXPOSE YO UR FACE O VER THE ENG INE AREA.TA KE PR ECA UTIO NS TO PR EV EN T O ILLEAKA GE O NTO THE EN GIN E.

W HENEVER THE ENG INE IS RUNN ING W ITHTHE VALVE CO VERS REM OVED, O ILSPLASH ING IN THE ENG INE AREA COULDC AU SE P ER SO NA L IN JU RY .

1. Start the engine and allow to run for a few minutes.2. Manually activate and release the engine brake

solenoid several times to allow the housing to be filled

with oi l. This is done by depressing the solenoid disc orinserting a small rod into the hole on the top of thesolenoid (see Fig. 18).

NOTE:PLACE RAG O VER CONTRO L VALVE ANDACCUM ULATOR COVERS TO REDUCE O ILSPRAY.

3. Watch the master piston to be sure it is moving downonto the injector rocker arm pad.

4. Watch the slave piston assembly. It should move downto contact the pin in the exhaust valve screw.

5. Repeat Steps 2 - 4 for each housing to insure properfunction.

6. Shut down engine. Clean the gasket surface for thecover.

Rocker Cover InstallationBe sure the seal is seated in the groove of the cover andinstall the cover on the spacer (Fig. 19). Install the Jacobs'bolts, six per cover. Final torque is 12 3 Nom (9 2 lb.-ft.).Tighten in steps to assure uniform compression of the sealsin accordance with Caterpillar procedures.

!6CAUT ION!

BE SURE TO TIG HTEN ALL ROCKER CO VERBO LT S E VE NLY . E XC ES SIV E O R U NE VE NT IGHTEN ING M AY CAUSE THE ROCKERC OVE R TO C RA CK.

Chassis WiringConsult vehicle manufacturer's wiring diagrams to locateengine brake switch location and wire coding. The brakecontrol function is performed by the engine electroniccontrol module.

NOTE:1996 AND LATER MO DEL TRUCKS SHOULDH AVE E NG IN E BR AKE C ON TR OL W IR IN GLOCATED BEH IND THE DASH . LOCATE THEAPPROPRIATE W IRES AND CONNECT TOCORR E CT V E HIC LE M A NU FA C TU R ER 'SSW ITCH. SW ITCH MAY NEED TO BEP RO CU RE D FR OM V EH IC LE M AN UF AC TU RE R.

Jacobs' Cab Control Group, PIN 020280, can be used ifdash switches are required. This group includes the lowresistance gold contact switches required to interface withthe engine electronic control module.

IN STALLAT IO N M AN UAL FO R M OD ELS 31 O N312A 9


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Section 5: Engine Brake MaintenanceTheory of OperationEnergizing the engine brake effectively converts a powerproducing diesel engine into a power absorbing aircompressor. This is a accomplished by opening thecylinder's exhaust valves near the top of the normalcompression stroke, releasing the compressed cylindercharge back into the atmosphere.The blow-down of the compressed cylinder charge toatmosphere prevents return of the stored energy to thepiston on the expansion stroke. The effect is a net energyloss, since the work done in compressing the cylindercharge is not returned to the crankshaft during theexpansion stroke. The energy being lost is drawn from theforward motion of the vehicle. The effect is to slow thevehicle on level roads and help control vehicle speeds ondownhill grades.The power required to operate the brake is obtained fromthe engine's cam shaft and rocker arms. The motion of theinjector rocker arm for the braking cylinder is utilized toopen the exhaust valve and blow-down the cylinder.Energizing the solenoid valve (1) permits engine lubricatingoil to flow under pressure to the accumulator (2) andthrough the control valve (3) to the slave piston (4) andmaster piston (5). The oil pressure causes the master piston(5) to descend down and come to rest on the injectorrocker arm (6).

The injector rocker arm (6) moves up, as it normally doesdue to injector cam lobe rotation, forcing the master piston(5) back into the brake housing. This creates a highpressure in the oil passage between the master piston (5)and slave piston (4) of the braking cylinder. The ball checkvalve in the control valve (3) traps the high pressure oil inthe master/slave piston hydraulic circuitThe high pressure created by the motion of the masterpiston (5) causes the slave piston (4) to move down.After traveling the clearance set during brake installation,the slave piston (4) contacts the valve actuating screw andpin assembly (7). Prior to the piston reaching the top deadcenter position, the exhaust valve (8) isforced openreleasing the compressed cylinder charge into the exhaustmanifold. Slave piston (4) travel is limited when theD-Lash"" adjust ing screw (9) uncovers a passageway inthe slave piston (4). This allows oil to flow back to the lowpressure side of the control valve (3), where i t is stored inthe accumulator (2) for the next braking cycle.The compressed cylinder charge released into the exhaustmanifold flows through the turbocharger as it escapes backto the atmosphere. The energy in the released chargespins the turbocharger and increases the intake manifoldpressure. This helps to increase the overall engine brakingeffect.

F IG . 2010 IN ST AL LA TIO N M AN UA L F OR M OD EL S 31 ON312A


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iii D-LASHTW~ ASSEMBLY

MASTERP ISTONASSEMBLY

FIG . 21

Engine Brake OverhaulProcedures

The Jacobs Engine Brake is a relatively trouble-free andmaintenance-free device. However, inspections and routinemaintenance are necessary to assure proper operation. Usethe following procedures to keep the engine brake in topcondition.This section wi ll cover how to properly remove, clean andreinstall engine brake components. Use an OSHA-approvedcleaning solvent when washing parts. Be sure to coat partswith clean engine oil when reinstalling them.

N EVER REM OVE AN Y ENG IN E BR AKEC OM PO NE NT W ITH E NG IN E R UN NIN G.P ER SO NA L IN JU RY M AY R ES UL T.

IN STA LLA TIO N M AN UA L F OR M OD ELS 310N 312A II


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Solenoid Valve 7/8" 12-POINTSTYLEI itCAUTION I

DO NOT DISASSEMBLE OR TAMPERWITH THESOlENOID VAlVE. ENGINE DAMAGE COULDRESULT.THE SOlENOID VALVE IS NOT AELDSERVICEABLE.

1. Disconnect solenoid harness. Using 7/8" 12-point or3/4" 6-point socket (based on solenoid type) andextension, unscrew solenoid valve.

2. Remove and discard the three rubber seal rings (seeFig. 22). If the lower ring stays in the bottom of thehousing solenoid bore, remove with a seal pick.

3. Wash out the solenoid valve with approved cleaningsolvent Use a brush to clean the oil screen. Whenclean, dry the valve with compressed air.

4. Clean out the solenoid valve bore in the housing. Useclean paper towels. Never use rags as they may leavelint and residue which can plug the oil passageways.

5. Coat the new solenoid seal rings with clean engine oil.Install the upper and center seal rings on the solenoidbody and the lower seal ring into the bottom of thesolenoid bore in the housing (see Fig. 23).

6. Be sure the seals are seated properly and carefullyscrew the solenoid into the housing without unseatingthe seals. Be careful not to twist the seals whileinstalling.

7. Torque the solenoid with the 7/8" 12-point head to12.5 Nom (110 lb.-in.). Torque the solenoid with the3/4" 6-point head to 20 Nom (180 lb.-in.).

:3/4" 6-POINT STYLE

eUPrERSEAL0CENTERSEAL ~gLOWERSEAL CFIG. 22

FIG. 23

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F IG . 24

Control Valve

W EAR S AFETY G lASS ES. R EM OV E C ON TRO LV ALV E C OV ER S C AR EF ULLY T O A VO IDP ER SO NA L IN JU RY . C ON TR OL V ALV E C OV ER SARE UNDER LOAD FROM THE CONTROLV A LV E S P RI NG S .

1. Push down on the control valve cover (1) using theappropriate diameter rod. Remove retaining ring (2)using retaining ring pliers (see Fig.24).

2. Slowly remove the control valve cover until springpressure ceases, then remove the two control valvesprings (3).

3. Using needle-nose pliers, reach into the bore and graspthe stem of the control valve (4) (see Fig. 24). Removethe control valve.

4. Wash the control valves with approved cleaningsolvent. Insert a wire into the hole in the base of thevalve until it contacts the ball check. The ball shouldlift with light pressure on the wire. If the ball is stuck,replace the control valve. D ry the valve withcompressed air and wipe clean with a paper towel.

5. Thoroughly clean the control valve bore in the housingusing clean paper towels. Never use rags as they mayleave lint and residue which can plug the oilpassageways.

6. Coat the parts with clean engine oil. Reassemble partsreversing the removal procedure.

IN STALlA TIO N M AN UAL FO R M OD ELS 310N312A 13


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Accumulator

WEA R S AF ET Y G lA SS ES . T HE A CC UM UL AT ORS PR IN G IS U ND ER S TR ON G C OM PR ES SIO N.USE CAUTION WHEN REMOVING THER ETAIN ING R ING AN D CO VER .. IF THE SPR IN GIS A CC ID EN TA LL Y D IS CH AR GE D, P ER SO NA LIN JU RY M AY R ESU LT.

1. Push down on the accumulator cover (1) using theappropriate diameter rod. Remove the retaining ring(2) using retaining ring pliers (see Fig.25).

2. Slowly remove the accumulator cover until springpressure ceases, then remove the cover and spring (3).

3. Use a magnet to remove the piston from theaccumulator bore.

4. Inspect the parts for wear or damage; replace ifneeded.

5. Thoroughly clean the accumulator bore in the housingusing clean paper towels. Never use rags as they mayleave lint and residue which can plug the oilpassageways.

6. Coat the parts with clean engine oil. Reassemble byinstall ing the piston, spring, cover and retaining ring,reversing the removal procedure.

Slave Piston AdjustingScrew (D-LashTM)1. Loosen the slave piston adjusting screw locknut and

remove the adjusting screw from housing (see Fig.26).NOTE:THE PART NUMBER FOR THE SCREW ISLOCATED AT THE TOP OF THE SCREW NEXTTO TH E SC REW DRIVER SLO T. REFER TO TH EPARTS M AN UAL FO R PR OPER PART N UM BERIDENTIFICATION.

I LtCAUTION IDO NOT ADJUST OR TAMPER W ITH THEA DJU STIN G S CR EW A SS EM BLY . E NG IN EDAM AG E CO ULD RESULT .

2. Wash the adjusting screw in an approved cleaningsolvent.

3. Inspect the slave piston adjusting screw. The plungershould protrude from the bottom of the screw andshould move freely (see Fig.27). Replace the entirescrew assembly if any defect is found.

14

FIG. 25

FIG.2Ei

D-LA5HTM

~FREE-MOVINGPLUNGERFIG. 27

IN STALLATION M ANU AL FO R M ODELS 310N312A


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F IG . 28

Master Piston

W EA R S AF ET Y G LA SS ES . T HE M AS TE R P IS TO NS PR IN G IS U ND ER S TR ON G C OM PR ES SIO N.USE CAUT ION W HEN REMOVING THER ETAIN IN G R IN G AN D C OVE R .. IF TH E SPR INGIS A CC ID EN TA LLY D IS CH AR GE D, P ER SO NA LIN JU RY M AY R ES ULT .

1. Press down on the master piston retaining washer torelieve the spring force. While holding the washer, usea pair of snap ring pliers to remove the retaining ringfrom the groove. Carefully release the retainer andremove it along with the old spring.

2. Remove master piston from bore. Clean in approvedcleaning solvent. Inspect for wear on the piston andfoot. Also inspect the bore.

3. Reinstall the master piston return spring by insertingthe small end into the bore. The large coil, identi fiedby WHITE paint, s ho uld b e faCing out

4. Place the retaining washer and snap ring over the footof the master piston and compress them into the bore.Using snap ring pliers, replace the snap ring in thegroove to retain the master piston (see Fig. 28).

5. Ensure the snap ring is properly engaged in the grooveby gently grasping the master piston foot and pul lingout until the master piston bottoms on the retainingwasher. Release the master piston. If the assembly iscorrect, all parts should return to their original position.

NOTE :AFTER TH E SP RIN G IS IN STALLED W ITH IN TH ERETAIN ING W ASHER AND SNAP R ING , IT ISNORMAL TO BE ABLE TO SEE THE SPR ING INTHE BORE AROUND THE RETAIN ING W ASHER .

IN STALLAT IO N M ANU AL FO R M OD ELS 310A /312A 15


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Slave Piston

W EA R S AF ETY G LA SS ES . T HE S LA VE P IS TO N ISR ET AIN ED BY S PR IN GS T HA T A RE U ND ERH EA VY C OM PR ES SIO N. IF T HE F OL LO WIN GIN STR UC TION S AR E N OT FOLLOW ED AN DP RO PE R TO OLS N OT U SE D, TH E S PR IN GSW ILL BE D ISCH AR GED W ITH ENOU GH FO RC ETO C AU SE P ER SO NA L IN JU RY .

1. Remove the locknut (3) on the slave piston adjustingscrew (1). Back out the adjusting screw until the slavepiston isfully retracted (screw is loose).

2. Place the hole in the clamp fixture (2) over the slavepiston adjust ing screw (see Fig.29).

3. While holding the fixture in position, screw holderdown over the slave piston (4) until the spring retainer(7) is contacted.

4. Turn the handle slowly until the retainer is depressedto about 1 mm (0.040',), relieving pressure against theretaining ring (8).

5. Remove the retaining ring using retaining ring pliers.Back out the holder until the springs (5 and 6) areloose. Remove the fixture.

6. Remove all components, ensuring there is no bindingor burrs. Clean in an approved cleaning solvent. Inspectparts and replace as necessary.

NOTE:BE S UR E C OM PO NE NT S A RE R EA SS EM BLE DIN P RO PE R O RD ER (S EE FIG . 30).

7. Use the clamp fixture to reinstall piston and springs. Besure retaining ring is placed on the retainer beforescrewing the clamp-holder down over the slave piston.

8. Compress the slave piston springs down until theretainer is about 1 mm (0.040'') below the retainingring groove. Reinstall the retaining ring. Be sure theretaining ring isfully seated in the groove.

9. Remove the clamp fixture slowly to insure properseating of retaining ring.

FIG . 29

4

FIG. :30

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Screw and Pin AssemblyReplacement Procedure

F IG . :3 1

Under normal use, the valve actuating screw and pinassembly does not need to be adjusted. Should the needarise to replace the pin and screw assembly or theguideless bridge, use the following procedure to set theproper height adjustment. (The pin and screw assemblyand locknut are Jacobs parts; the bridge is a Caterpillarpart.)1. Place the exhaust valve bridge (1, Fig.31) in a soft jawvice. Remove the lock nut (2) and the screw and pinassembly (3). Note that these parts are assembled

using a thread retaining compound. Any partsdamaged during disassembly must be replaced.2. Clean the parts to be assembled with an appropriatesolvent (Loctite" 755 or equivalent). A primer isrecommended to ensure quick setting of the retainingcompound.W ith Ja cobs A ssem bly T ool, PIN 0197643. place the bridge on the assembly tool (4) with therecesses in the bridge over the pins on the tool. Clamp

the bridge flush against the assembly tool in a soft jawvice.4. Apply retaining compound to the screw body threads(Loctite' 620 or equivalent). Install the screw and pinassembly and lock nut into the bridge. Turn the screw

and pin assembly clockwise until itcontacts theassembly tool pin.5. Torque the locknut to 24 Nom(lS lb.-ft.).W ith ou t Ja cob s A ssem b ly T o ol,P IN 0197646. Measure and record the depth of the pocket in the endof the bridge opposite the pin and screw assemblywith a depth gage.7. Apply retaining compound to the screw body threads

(Loctite" 620 or equivalent). Install the screw and pinassembly and lock nut into the bridge.S. Turn the screw and pin assembly clockwise until thedepth from the bottom surface of the bridge to the

face of the valve actuating pin equals the depthmeasured in Step 6.9. Torque the locknut to 24 Nom (lSlb.-ft.). Check the

depth of the actuating pin to ensure it did not shiftduring torquing.

IN ST AL LA TIO N M AN UA L F OR M OD ELS 3 10 A/312 A 17


18/19

NOTES

IN STALLAT IO N M AN UAL FO R M OD ELS 310N312A 19


19/19

J ac ob s' a nd J ak e B ra ke " a re re gis te re d tra demark s a nd D - La sh TWs a tr ad ema rk o fJ a cob sV eh ic le Equi pmen t Compan y

2 2 E ast D u dle y T ow n R oa dB lo om fie ld C T 0 6 00 2

jacobs brake caterpillar c10 & c12 installation instructions 021222b

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