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Maintenance manual no. MM-0153

Stopmaster Wedge BrakeIssue 03/2007

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2 ArvinMeritor Stopmaster Wedge Brake

Service Notes

Before You BeginThis publication provides installation and maintenance procedures

for the Stopmaster Wedge Brake.

The information contained in this publication was current at the

time of printing and is subject to revision without notice or liability.

You must understand all procedures and instructions before you

begin maintenance and service procedures.

You must follow your company's maintenance and

service guidelines.

You must use special tools, when required, to avoid serious

personal injury and damage to components.

ArvinMeritor uses the following notations to alert the user of

possible safety issues and to provide information that will help to

prevent damage to equipment and components.

WARNING

A WARNING indicates a procedure that you must follow

exactly to avoid serious personal injury.

CAUTION

A CAUTION indicates a procedure that you must follow

exactly to avoid damaging equipment or components.

Serious personal injury can also occur.

NOTE:A note indicates an operational, procedure or instruction

that is important for proper service. A NOTE can also supply

information that will help to make service quicker and easier.

This symbol indicates that you must tighten fasteners to a

specific torque.

Information contained in this publication was in effect at the time the

publication was approved for printing and is subject to change without notice

or liability. ArvinMeritor Commercial Vehicle Systems reserves the right to revise

the information presented and to discontinue the production of parts described

at any time.

Safety Instructions Observe the manufacturers safety instructions for jacking up

and securing the vehicle

Only use original ArvinMeritor parts

Use only the tools recommended

Observe the following service instructions and notes

When working on the brake you must ensure that it cannot be

activated inadvertently

Never use compressed air to remove brake dust or for the

purpose of drying. Any type of dust can be injurious to health if

inhaled. Use ArvinMeritor brake cleaner for cleaning the brake.

When removing or fitting a complete brake, you should

remember it has a dead weight of up to 117lbs (53kg). Use a

lifting system, taking care not to damage the brake.

When the servicing has been completed, it is essential that you

road test the vehicle and try out the brakes.

Access Information on ArvinMeritor's Web

SiteAdditional maintenance and service information for ArvinMeritor's

commercial vehicle systems component lineup is also available at

www.meritorhvs.com

To access information go to Products & Services Icon; from drop

down menu click on Literature on Demand. The screen will

display an index of publications by type.
http://www.meritorhvs.com/LODSearch.aspx?flag=1&product_id=15&publication=Servicehttp://www.meritorhvs.com/LODSearch.aspx?flag=1&product_id=15&publication=Servicehttp://www.meritorhvs.com/LODSearch.aspx?flag=1&product_id=15&publication=Service

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3ArvinMeritor Stopmaster Wedge Brake

Terms used in this manual

Manufacturer:

ARVINMERITOR

Manual

Maintenance manual no. 0153

Device:

Stopmaster Wedge Brake

Technician:Qualified personnel working on brake maintenance and servicing.

Maintenance and servicing:

Maintenance and servicing refer to periodical checks and/or

replacement of the Stopmaster brake parts or components. It

also refers to the determining of the cause of a malfunction in

order to restore the initial operating conditions.

Operator:

Any person who will use the Stopmaster brake as part of a more

complex device.

Warranty

Warranty applies to the Stopmaster brake installed on vehicles

for which it was designed. Warranty is void in the following cases:

Improper use of the vehicle on which the Stopmaster brake is

installed (usage conditions, overloading etc.)

Tampering with vehicle components that may affect brake

performance.

Use of non-original spare parts.

Improper installation, adjustment, repair or modification.

Poor or improper maintenance (including consumables other

than those specified).

Further information on warranty conditions may be obtained

directly from the manufacturer or by referring to the ArvinMeritor

web sitewww.meritorhvs.com

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Contents

2 General information2 Introduction

2 Symbols

2 Safety precautions

3 Warranty

5 Section 1 - Description

7 Field of application

8 Stopmaster II Duplex brake - exploded view

9 Stopmaster II Duplex brake - parts list

10 Stopmaster II Simplex brake - exploded view

11 Stopmaster II Simplex brake - parts list

12 Stopmaster E Simplex brake - exploded view

13 Stopmaster E Simplex brake - parts list

14 Stopmaster E Duplex brake - exploded view

15 Stopmaster E Duplex brake - parts list

16 Stopmaster wedge brake operation

17 Self-Adjustment Mechanism Operation

18 Stopmaster II - Stopmaster E Brakes lubrication instructions

19 Section 3 - Maintenance

20 Stopmaster brake preventive maintenance

21 Brake disassembly24 Checking components

27 Technical assembly data

28 Reassembly

37 Section 4 - Troubleshooting

38 Troubleshooting

pg.

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pg.

1

Description

7 Field of application

8 Stopmaster II Duplex brake - exploded view

9 Stopmaster II Duplex brake - parts list

10 Stopmaster II Simplex brake - exploded view

11 Stopmaster II Simplex brake - parts list

12 Stopmaster E Simplex brake - exploded view

13 Stopmaster E Simplex brake - parts list

14 Stopmaster E Duplex brake - exploded view

15 Stopmaster E Duplex brake - parts list

16 Stopmaster wedge brake operation

17 Self-Adjustment Mechanism Operation

18 Stopmaster II - Stopmaster E Brakes lubrication

instructions

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Field of applicationThe Stopmaster brake is available in two versions:

STOPMASTER II

STOPMASTER E

Both brake types are similar in design except that the actuation

parts of the Stopmaster E version are physically bigger than

those of the Stopmaster II.

Stopmaster brakes are wedge actuated with power provided by

air cylinders or in special applications by hydraulic cylinders.

They can be equipped with integral spring brake units for parking

and emergency braking.

The brake power unit forces a wedge between two rollers and two

plungers which, being pushed in opposite directions, press the

brake shoes against the brake drum.

Stopmaster brakes utilise either one power unit (Simplex

actuation) or two power units (Duplex actuation).

When two power units are used either or both can incorporate an

integral spring brake facility.

1 Description

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Exploded viewStopmaster II Duplex

2

3

4

5

9

10

8

6

735

33

34

29

30

20

3234

31

1918

1716

15

1413

25

26

27

28

11

12

24 23

2221

1

29

30

25A

29A

Alternative

one piece

dustshield

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1

2

3

4

5

6

7

8

9

10

1112

13

14

15

16

17

18

19

20

21

22

23

24

25

25A

26

27

28

29

29A

30

31

32

33

34

35

Stopmaster II DuplexBrake Components

Ref. Description

Brake spider

Adjusting bolt

Seal - adjuster plunger

Actuator (adjusting bolt sleeve)

Adjusting plunger

Anchor plunger

Seal - anchor plunger

Gasket

Guide pawl assembly

Guide screw

Wedge assemblyCollet nut

Cotter pin

Washer

Wedge spring

Rubber boot seal

Wedge washer

Roller cage

Rollers

Wedge

Nut

Washer

Hold-down clip

Screw

Dustshield (half)

Dustshield

Rubber plug (round)

Screw

Rubber plug (long)

Brake shoe and lining assembly

Brake shoe and lining assembly R+R (rolled and relieved)

Brake shoe return spring

Service grease

Identification plate

Customer logo plate

Rivet

Wear sensor

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Exploded viewStopmaster II Simplex

2

3

4

5

9

9

8

5

4

7

6

3

2

35

33

34

29

30

20

3234

31

1918

1716

15

14

13

25

26

27

28

6

1

36

24 23 22 21

12

11

810

29

30

25A

29A

Alternative

one piece

dustshield

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1

2

3

4

5

6

7

8

9

10

1112

13

14

15

16

17

18

19

20

21

22

23

24

25

25A

26

27

28

29

29A

30

31

32

33

34

35

36

Stopmaster II SimplexBrake Components

Ref Description

Brake spider

Adjusting bolt


Actuator (adjusting bolt sleeve)

Adjusting plunger

Anchor plunger


Gasket

Guide pawl assembly

Guide screw


Cotter pin

Washer

Wedge spring

Rubber boot seal

Wedge washer

Roller cage

Rollers

Wedge

Nut

Washer

Hold-down clip

Screw

Dustshield (half)

Dustshield

Rubber plug (round)

Screw

Rubber plug (long)


Brake shoe and lining assembly R+R (rolled and relieved)


Service grease


Customer logo plate

Rivet

Wear sensor

Plug (anchor box)

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Exploded viewStopmaster E Simplex

2

3

4

5

30

29

35

31

30

20

1918

1716A

16 15

14 13

28

27

25

24 23

21

6

6

32

341

9 8

33

34

9

12

11

29

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1

2

3

4

5

6

7

8

9

10

1112

13

14

15

16

16A

17

18

19

20

21

22

23

24

25

26

27

28

29

30

31

32

33

34

35

Stopmaster E SimplexBrake Components

Ref. Description

Brake spider

Adjusting bolt


Actuator

Adjusting plunger

Anchor plunger

(Not used)

Gasket

Guide pawl assembly

(Not used)


E clip

Washer

Wedge spring

Special washer

Boot seal

Wedge washer

Roller cage

Rollers

Wedge

Nut

(Not used)

Hold-down clip

Screw

Dustshield

(Not used)

Screw

Rubber plug (long)



Service grease


Customer logo plate

Rivet

Wear sensor

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Exploded viewStopmaster E Duplex

2

3

4

5

30

33

9

10

6

8

7

35

29

31

36

30

2019

1817

1516

14

13

25

27

28

26

12

3234

11

12

29

2122

2324

26A

27A

16A1

34

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1

2

3

4

5

6

7

8

9

10

1112

13

14

15

16

16A

17

18

19

20

21

22

23

24

25

26

26A

27

27A

28

29

30

31

32

33

34

35

36

Stopmaster E DuplexBrake Components

Ref. Description

Brake spider

Adjusting bolt


Actuator

Adjusting plunger

Anchor plunger


O ring

Guide pawl assembly

Guide pin


E clip

Washer

Wedge spring

Special washer

Boot seal

Wedge washer

Roller cage

Rollers

Wedge

Nut

Washer

Hold-down clip

Screw

Dustshield

Rubber plug (round)

Rubber plug (round)

Screw

Spring washer

Rubber plug (long)



Actuator service grease


Customer logo plate

Rivet

Wear sensor

Brake shoe service grease

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Stopmaster Wedge Brake OperationIn the brake released position the wedge assembly is held

withdrawn by the wedge return spring while plungers are kept

closed on rollers and their abutment seats by the brake shoe

return spring. Fig. 1.1

When the brake is actuated the air chamber push rod forces the

wedge head between the rollers which spread apart and push the

plungers outwards causing the brake shoes to open. Plungers

are lifted off their abutment seats until shoes contact the brakedrum. Fig. 1.2

As shoes contact the drum, the latter under the action of the

friction linings drags the shoes in the direction of rotation while

brake shoes in turn transfer the friction force to anchor plungers.

This causes the shoe plunger to reseat on its abutment and

transfer the braking torque to the brake spider, in order to balance

the braking torque generated between shoes and drum. Fig. 1.3

When the brake is released the wedge spring returns the wedge

and air chamber diaphragm to the off position. The shoe and

lining is pulled away from the drum by the shoe return springs

and returns the plungers to their abutment seats in the housing.

Fig. 1.4

Fig. 1.1

Fig. 1.2

Fig. 1.3 Fig. 1.4

1 Description

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Self-Adjustment Mechanism OperationOn the brake application the adjuster bolt and sleeve assembly

moves outwards.

As the opposing chamfers of teeth on the adjuster sleeve and the

teeth on the guide pawl (A) move against each other the pawl is

lifted against the spring (B).

Fig. 1.5

When the brake lining to drum clearance exceeds its

predetermined limit the travel of the adjuster bolt and sleeve is

such that it allows the pawl to jump into the next tooth on the

adjuster sleeve.

Fig. 1.6

As the brake is released and the adjuster bolt and sleeve

assembly is returned to the off position, the guide pawl rotates

the sleeve anti-clockwise and unscrews it from the fixed adjusting

bolt. The lining to drum clearance is reduced, completing one

adjustment cycle. This is repeated each time the lining to drum

clearance is sufficient to allow further adjustments to take place.

Fig. 1.7

Fig. 1.5

Fig. 1.6

Fig. 1.7

1 Description

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1 Description

For STOPMASTER E brake units different types of lubricant are

used, according to the following table:

Lubrication points

1. The shoe and rest pads located on the spider.

2. The internal surface of the hold-down clips.

3. The shoe contact surface on the plungers.

4. The wedge assembly cavity.

5. All items of the auto-adjustment mechanism.

Stopmaster II - Stopmaster E BrakesLubrication instructions

General information

Experience shows that some lining specifications produce a type

of dust which has a drying (or caking) effect on brake

lubricants.

To ensure optimum braking performance the following lubrication

instructions, regarding lubricant specifications and lubrication

frequency should be adhered to. Lubrication intervals should beshortened where lubricant drying or caking is found to occur.

The standard lubrication interval for Stopmaster brake units is

every 160,000 km or 12 months, whichever comes first.

This is considered the maximum even under ideal operating

conditions.

Unusual temperatures or operating conditions will require different

lubrication intervals. Therefore comply at all times with lubrication

instructions provided by the manufacturer.

The lubricant type should meet specifications of the ArvinMeritor

0-616-A standard: High temperature, waterproof grease to NLGI

Grade one available under ArvinMeritor RBSK 1022 part number

in 1 kg tins or RBSK 0253 in tubes.

Lubrication points Stopmaster II Stopmaster E

1 RBSK1022 - RBSK0253 Weicon AS450



4 RBSK1022 - RBSK0253 Simplex: RBSK 1022 - RBSK0253

Duplex: Klber Syntheso GLEP1

5 RBSK1022 - RBSK0253 Simplex: RBSK 1022 - RBSK0253

Duplex: Klber Syntheso GLEP1

Fig. 1.8

3

1

4

5

2

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pg.

2

Maintenance

20 Stopmaster brake preventive maintenance

21 Brake disassembly

24 Checking components

27 Technical assembly data

28 Reassembly

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2 Maintenance

Stopmaster brake preventive maintenance

Every 25,000 Km:

1. Check the lining to drum clearance.

2. If it is 1.5 mm or less, self-adjusters are efficient and there is

no need for any further action.

3. Check state of wear through the appropriate inspection plugs

located on the dustshield.

Fig. 2.1

At every reline:

1. Inspect the seals to see if they are worn, cut or torn.

If they are defective they must be replaced, and it also

becomes necessary to disassemble the actuating parts and

overhaul as required.

2. Lubricate the following areas:

1. The shoe rest pads located on the spider.

2. The internal surfaces of the hold-down clips.


Fig. 2.2

Every 160,000 Km:

1. Dismantle the actuating parts and check their condition.

Overhaul as necessary.

2. Lubricate brake in line with recommended lubrication

procedure.

Fig. 2.3

Fig. 2.1

Fig. 2.2

Fig. 2.3

1

3

2

Check lining wear

Check lining to drum

clearance (< 1.5 mm)

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2 Maintenance

Brake disassembly

WARNING

Chock and jack up the vehicle. Remove the wheel on which

you are going to operate.

When working on brakes, the spring brake chamber must be

kept in the off position by manually caging the spring (refer

to manufacturers instructions).

Remove the brake drum. If drums are worn, back off the shoe

and lining assemblies manually through the slots in the

dustshield, above or below the air chambers, using special tool.Engage tool in the square slot in the head of the adjusting bolts

and adjust as required to increase drum to lining clearance.

Fig. 2.4

STOPMASTER II

Tool no. RBSK 0187

STOPMASTER E

Tool no. RBSK 1420

Remove the brake shoe return springs using special tool.

STOPMASTER II and E

Tool no. RBSK 0185

Fig. 2.5

Remove the brake shoe and check the condition of the hold-down

clip as illustrated (Fig. 2.6).

A = 6.7 mm max,

maximum shoe web thickness 8 mm

A = 10 mm max,

maximum shoe web thickness 12 mm

Fig. 2.4

Fig. 2.5

Fig. 2.6

Stopmaster

ETool no. RS410E

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2 Maintenance

Remove the dustshield, if necessary. - Fig. 2.7

Unscrew the air chambers and slacken off the collect nut to

separate the air chambers from the brake spider or by removing

the four capscrews on flange mounted type. - Fig. 2.8

Remove the wedge assembly from its housing.- Fig. 2.9

Unscrew and remove the guide pawl assembly and the anchor

plunger guide screw. - Fig. 2.10

Fig. 2.7

Fig. 2.8

Fig. 2.9 Fig. 2.10

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Fig. 2.11

Fig. 2.12

Fig. 2.13 Fig. 2.14

2 Maintenance

Drift the seals clear of their bores in the housing, using an

appropriate tool.- Fig. 2.11

Remove the adjusting bolt and sleeve assembly and the auto

adjust and anchor plungers. - Fig. 2.12

Dismantle the adjusting bolt assembly and carefully clean all

parts. Check for wear and damage. - Fig. 2.13

Replace all worn or damaged parts and always renew seals.

Fig. 2.14

WARNING

When replacement wedge assemblies or plungers are

required, ensure the replacement parts have the same

wedge angles as the displaced parts.

Wedge stem

LOCATION OF ANGLE MARKING

Plunger end faces

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2 Maintenance

Checking Components

Adjusting Pawl

The scored, rounded teeth of the adjusting pawl on the left are

unacceptable and the part must be discarded and replaced, while

the teeth of the pawl on the right are still undamaged.

This part may be re-used. However, if you have any doubts,

always replace the pawl.- Fig. 2.15

Internally scored Adjusting Plunger

If the internal scoring of an adjusting plunger consists of only light

markings the plunger may be re-used.

However, if the scoring is rough the part must be replaced.

Fig. 2.16

Adjusting Plunger

The light contact marks on the pawl guide slot in the adjusting

plunger shown on the left are acceptable and will not hamper

performance.

The deep scoring shown on the right is unacceptable and this

plunger must be replaced.

Fig. 2.17

Fig. 2.15

Fig. 2.16

Fig. 2.17

Adjusting Pawl

Scored rounded teeth

(replace part)

Internally scored Adjusting Plunger

light markings (re-use part)

rough markings or scores (replace part)

Adjusting Plunger

Straight undamaged teeth

(re-use part)

Light contact marks

(re-use part)

Scored pawl guide slot

(replace part)

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Fig. 2.18

Fig. 2.19

Fig. 2.20

2 Maintenance

Adjusting Plunger

Shown here on the right is a normal roller contact patch on the

ramp of an adjusting plunger and this part may be re-used.

On the right we see the rectangular indentation of a brinelled

roller ramp.

This plunger must be replaced. - Fig. 2.18

Actuators

Both of these actuators show normal sign of wear and are re-

usable. - Fig. 2.19

While the abnormal wear or damage on these actuators is

unacceptable and these parts must be replaced. - Fig. 2.20

Adjusting Plunger

Normal roller contact patch

(re-use part)

Brinelled roller ramp

(replace part)

Actuators

normal wear

(re-use part)

normal wear

(re-use part)

Actuators

Metal displacementalong tooth axis

(replace part)

Damaged teeth(replace part)

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2 Maintenance

Duplex BrakeReassembly

In the reassembly of the brake, always ensure that the adjuster

bolt and sleeve assembly is positioned at the leading end of the

shoe and the anchor plunger is at the trailing end (see

illustration).

STOPMASTER E shoes are stamped with the wordANCHORon

the anchor end.

STOPMASTER II shoes are stamped with the word DRUM

rotation and an arrow.

When reassembling install both shoes with arrow following drum

rotation.

Fig. 2.21

Simplex BrakeReassembly

STOPMASTER E shoes are stamped with the wordANCHORon

the anchor end.

NOTE:Any change to the brake system may require type

approval. Therefore use only original ArvinMeritor spare parts.

Fig. 2.22

Fig. 2.21

Fig. 2.22

Drum rotation

Drum rotation

Anchor

plunger

Adjusting

plunger

Adjusting

plunger

Adjusting

plunger

Adjusting

plunger

Anchorplunger

Anchorplunger

Anchorplunger

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2 Maintenance

Technical assembly data

Tightening torques Duplex Version Simplex Version

Guide pawl assembly 20-30 Nm 20-30 Nm

Guide screw 20-30 Nm

Hold-down clip screw 20-30 Nm 20-30 Nm

Dustshield screw 20-30 Nm 20-30 Nm

Air chamber collet nut 300 Nm 10 300 Nm 10

Air chamber f lange screw see vehicle manufacturers manual see vehicle manufacturers manual

Wear sensor 10-15 Nm 10-15 Nm

Stopmaster II Box plug 40 5 Nm

SETTING DIMENSIONS

Actuator assembly

Except where otherwise indicated dimensions are expressed in mm:

STOPMASTER II all types 144.5 0.5 142.5 0.5

STOPMASTER E 360 not applicable 152 0.5

381 144 0.5 151 0.5

410 162 0.5 164 0.5 (5/5)

167 0.5 (15/5)

169 0.5 (15/0)

Hold-down clip - Spacing: Shoe web thickness

STOPMASTER II A = 6.7 mm max 8 mm

STOPMASTER E A = 10 mm max 12 mm

STOPMASTER E A = 6.7 mm max 8 mm

Drum to lining clearance: 0.8 - 1.2 mm

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3

1

4

5

2

2 Maintenance

Fig. 2.23

Reassembly of the Brake

NOTE: Only original ArvinMeritor spare parts should be used.

ATTENTION

Use of non-original parts could seriously affect brake

performance.

Breathing the dust generated by friction of brake liningsagainst drum is hazardous to your health. Always wear the

assigned protective equipment when servicing brake units

and avoid remaining in the area unless your work requires

it.

Lubrication points

1. The shoe rest pads located on the brake spider.

2. The internal surface of the hold-down clips.


4. The wedge assembly cavity.

5. All items concerned with the self-adjustment mechanism.

Fig. 2.23

Lubricant Lubrication points Lubrication pointsAt brake reassembly use the following recommended lubricant types: STOPMASTER II STOPMASTER E

ArvinMeritor Service grease no. RBSK-0253 - RBSK 1022 1, 2, 3, 4, 5 4, 5 Simplex

Weicon Antiseize AS450 grease 1, 2, 3

Klbler Syntheso GLEP1 grease 4, 5 Duplex

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Grease inner bores of brake spider plunger housing. Fig. 2.24

Lightly grease the neck of the seal and carefully assemble onto

the anchor plunger.

Note the anchor and adjuster seals are different in design.

Ensure the right seal is fitted, as follows:

Anchor plunger = short seal

Adjuster plunger = long seal

Fig. 2.25

Evenly coat with grease the entire cylindrical surface of theanchor plunger.

Locate the anchor plunger into housing, ensuring the slot aligns

correctly with the guide screw tapped hole.

Fig. 2.26

2 Maintenance

Fig. 2.24

Fig. 2.25

Fig. 2.26

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Fit guide screw and tighten to torque to 20-30 Nm.

Fig. 2.27

Evenly coat with grease the entire cylindrical surface of the

adjusting plunger.

Locate the adjusting plunger into housing, ensuring the slot aligns

correctly with the guide pawl hole.

Fig. 2.28

Lightly grease the guide pawl and fit, screwing it in one turn only.

Check that the guide pawl moves freely through its bore and with

the plunger slot. Note that the guide pawl has a raised ridge

which locates into a groove in the brake spider.

Remove the guide pawl.

Fig. 2.29

2 Maintenance

Fig. 2.27

Fig. 2.28

Fig. 2.29

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2 Maintenance

Fig. 2.30

Fig. 2.31

Fig. 2.32

Lightly grease the adjuster seal neck and carefully assemble onto

adjusting bolt; grease bolt threads.

Fig. 2.30

Grease actuator threads and screw onto the adjusting bolt (large

chamfer towards bolt head). - Fig. 2.31

ATTENTION:

Ensure actuator is screwed in the correct direction.

Check chamfers.

Threads must not be tight as this would cause adjustment

not to function correctly

Ensure the adjusting bolt does not protrude through the

actuator as this would also inhibit adjustment.

Grease the actuator outer surface.

Then fit adjusting bolt and sleeve (with slight rotation) into theadjusting plunger.

Fig. 2.32

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2 Maintenance

Fig. 2.33

Fig. 2.34

Fig. 2.35

Fit guide pawl ensuring correct alignment and torque to 20-30

Nm.- Fig. 2.33

Seat seals using seal driver. Note that the shoe retainer on the

bolt head must align with the slot in the seal driver. Fig. 2.34

STOPMASTER II Tool no. RBSK 0186

STOPMASTER

E Tool no. RBSK 1427

Through the wedge bore, fill the housing with approx 29 g of

grease, coat with grease the wedge assembly and fit into bore

aligning the raised ridges on the wedge with the correspondingslots in the wedge bore; press wedge in by hand up to plunger

travel starting point.

Fig. 2.35

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2 Maintenance

Fig. 2.36

Fig. 2.37

Fig. 2.38

Screw collet nut fully onto the air cylinder and then screw in the

air chamber till it bottoms in the housing ensuring the collet nut is

still free to turn. In order to align air ports unscrew the chamber

to a maximum of one full turn, if necessary.

Tighten collet nut to a torque of 300 Nm 10.

Fit the spring brake chamber in a similar manner but ensure the

spring is fully caged.

On flange type models locate the chamber to the spider.

Fit the retaining capscrew and tighten to the torque

recommended in the vehicle Manufacturers Workshop Manual.

If previously removed, refit dustshield halves and tighten screws

to a torque of 20-30Nm.

One piece dustshields must be fitted prior to reassembling air

chambers.

Refit brake shoe hold-down clips and tighten to 20-30 Nm

torque. Ensure clip condition conforms to specifications (see

page 19 for details).

Set dimension over brake shoe contact surfaces. Ensure caliper

is flat on adjusting bolt at the shoe web contact surface. On

Duplex models repeat the same operation on the opposite side.

Fig. 2.38

Except where otherwise indicated, dimensions are expressed in

mm

STOPMASTER II DUPLEX SIMPLEX

all sizes 144.5 0.5 142.5 0.5

STOPMASTER E DUPLEX SIMPLEX

360 152 0.5

381 144 0.5 151 0.5

410 162.5 0.5 164 0.5 (5/5)

167 0.5 (15/5)

169 0.5 (15/0)

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2 Maintenance

Fig. 2.39

Fig. 2.40

Fig. 2.41

Position the shoe return springs in the upper shoe as illustrated

and fit the shoes ensuring that the short radius locates against

the adjusting bolt assembly. Fit the springs with special tool.

Fig. 2.39

ATTENTION

Take care not to touch the seals to prevent seal damage

during this operation.

STOPMASTER II and STOPMASTER E:

Tool no. RBSK 0185

Measure the brake drum diameter at various points around thedrum and record the readings taken. - Fig. 2.41

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Centralize both brake shoes and measure the brake lining

diameter as illustrated. (When setting, it is important to ensure

that the spring brake is still totally caged). - Fig. 2.42

Standard brake shoe data

Dimensions are expressed in mm

Brake type STOPMASTER II STOPMASTER E

360 358 0.5 358,5 0.5381 379 0.5 379 0.5

394 392 0.5

410 408 0.5 408,5 0.5

Adjust the lining diameter by turning the adjusting bolts by an

equal amount until the brake lining diameter is 2 mm less the

drum diameter previously recorded.

Fit the brake drums.

With long feeler gauge check clearances at shoe centres.

This should be between 0.8 and 1.2 mm.

If necessary readjust to obtain these clearances.

Fig. 2.43

Uncage the air chamber spring and refit air pipes.

Refit wheels and check brakes on a rolling road and test drive.

2 Maintenance

Fig. 2.42

Fig. 2.43

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pg.

3

Troubleshooting

38 Troubleshooting

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Self-adjustment

not functioning

Brakes dragging

Uneven lining wear

Insufficient brake

performance

Brake pulling

3Troubleshooting

1 Guide pawl spring is broken (9)

2 Worn or damaged pawl and/or actuator teeth (9, 4)

3 Adjusting bolt too tight in actuator (2, 4)

4 Brake shoe web not properly located in shoe retainer (2, 29)

5 Corroded adjustment parts (2, 4, 5, 9, 11)

6 Insufficient lubrication

1 Spring chamber not fully released

2 Air leak from spring chamber

3 Overstretched or broken brake shoe return springs (30)

4 Anchor/adjusting plungers are tight or seized up (5, 6)

5 Broken wedge spring

1 Reverse installation of brake shoe (short radius must be seated on adjusting bolt) (29)

2 Brakes are dragging - see Faults (2)

3 Unequal air chamber output

4 Damaged or broken hold-down clip

5 Brake drum diameter variations (tapering)

6 Dirt and/or grease on lining (29)

7 Variations in surface finish of brake drums1 Shoe to drum clearances too large

2 Worn linings

3 Unsuitable lining material

4 Grease or oil on linings

5 Input pressure too low

1 Air chamber installation depths incorrect

2 Unequal air chamber output

3 Different shoe drum clearances - see Faults (1)

4 Grease or oil on linings

5 Different brake drum material or surface finish

6 Different lining material

7 Broken wedge spring

8 Heavy dirt ingress

9 See also all Possible Causes described at Fault 3.

Possible causesFault

The following chart shows the most common faults occurring to Stopmaster brakes.

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ArvinMeritor Heavy Vehicle Braking Systems

Grange Road, Cwmbran Published in Italy

South Wales NP44 3XU - U.K.

Tel.: +44 (0) 1633 834238 Copyr ight 2002 Issued 01/ 2007Fax: +44 (0) 1633 834191

www.arvinmeritor.com ArvinMeritor Inc. M-graph - MM0153

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ArvinMeritor Heavy Vehicle Braking Systems

Grange Road, Cwmbran Published in Italy

South Wales NP44 3XU - U.K.

mm_0153

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