Remove/install brake booster

AR43.10-P-0350V

Remove/install brake booster

12.02.2019

Model

171 with engine 113, 271, 272

Modification notes

01.09.2010

"Perform brake test on test bench" reference changed

Test sequence augmented/revised

Shown on model 171.442

1a

Pendulum support

1b

Expansion reservoir

3

Wiper arms

4

Refrigerant pipe

5

Water collector

28

Retaining clamp

29

Retaining clamp

F1

Fuse and relay box

1

Tandem brake master cylinder

8

Vacuum line

9

Boot

18

Sealing ring

20

Connector

21

Seal

23

Nuts

A7/7

BAS brake booster

A7/7b1

BAS diaphragm travel sensor

A7/7s1

BAS release switch

A7/7x1

Diaphragm travel sensor connector

A7/7x2

Release switch and solenoid valve connector

B34/1

ESP brake pressure sensor 1

Shown on model 171.456

6a

Nuts

9

Boot

23

Nuts

25

Safety clip

26

Pin

F1

Fuse and relay box

 

Remove/install

 Caution

Risk of poisoning from swallowing brake fluid. Risk of injury from skin and eye contact with brake fluid

Only pour brake fluid into suitable and appropriately marked containers. Wear protective clothing and eye protection when handling brake fluid.

AS42.50-Z-0001-01A

Topical note

Notes on externally invisible brake fluid loss

AH42.10-P-9406-02A

Topical note

Brake fluid notes

AH42.50-P-0001-01A

Topical note

Notes on repairs to brake system

AH42.00-P-0003-01A

Topical note

Notes on self-locking nuts and bolts

AH00.00-N-0001-01A

1

Move wiper arms (3) into end position

2

Remove key from EIS electronic ignition lock control unit

3

Eliminate vacuum in BAS brake booster (A7/7)

 Operate brake pedal several times until vacuum in BAS brake booster (A7/7) is reduced.

 Warning

Risk of injury caused by fingers being jammed or pinched when removing, installing or aligning hoods, doors, trunk lid/rear-end door or sliding roof.

No parts of the body or limbs should be within the operating area when the components are moving.

AS00.00-Z-0011-01A

4

Open hood

AR88.40-P-1000V

 Warning

Injury hazard from pinching and crushing, in extreme cases extremities can even be cut off when caught in windshield wiper mechanism.

When working on the windshield wiper mechanism, always switch off the ignition and store transmitter key outside of transmission range (at least 2 m).

AS82.30-Z-0001-01A

5

Remove wiper arms (3)

Remove and install wiper arm

AR82.30-P-6100V

 Nut on wiper arm

*BA82.30-P-1004-01A

 Puller

*001589383300

6

Remove air/water duct (5)

AR83.25-P-1402V

7

Remove torsion bar linkage (1a) from tandem master brake cylinder (1)

AR42.10-P-0300-02V

8

Remove tandem master brake cylinder (1)

AR42.10-P-0310V

 Do not detach expansion reservoir (1b) for brake fluid from tandem master brake cylinder (1).

 Installation: Check tandem master brake cylinder (1) on primary piston for leak tightness.

 Installation: Replace sealing ring (18).

9

Release and disconnect diaphragm travel sensor connector coupling (A7/7x1) from BAS diaphragm travel sensor (A7/7b1)

10

Release and disconnect indicator switch and solenoid valve connector coupling (A7/7x2) from BAS indicator switch (A7/7s1)

11

Release and disconnect connector coupling (20) from ESP pressure sensor 1 (B34/1)

12

Remove vacuum line (8) from BAS brake booster (A7/7)

Model 171.442/445

AR43.10-P-0355V

Model 171.454/456/458/473

AR43.10-P-0355VA

13

Unclip refrigerant line (4) from retaining clamps (28, 29) and place to one side

Model 171.442/445

14

Remove left cover below instrument panel

AR68.10-P-1500V

15

Remove front cover of pedal assembly

AR29.10-P-0320V

16

Unscrew nuts (6a) from fuse and relay box (F1) in driver footwell

AR54.15-P-1256-01VA

 Nut, fuse and relay module to body

*BA54.15-P-1003-01A

 Bolt of clamping bracket for fuse and relay module to suspension strut tower

*BA54.15-P-1005-01A

17

Remove safety clip (25); to do so, remove bolt (26)

18

Unscrew nuts (23) from BAS brake booster (A7/7)

 Nut, brake booster carrier to front end

*BA43.10-P-1002-01A

19

Release fuse and relay box (F1) in engine compartment

AR54.15-P-1256-01VA

 Pull fuse and relay box (F1) out of bulkhead.

 Nut, fuse and relay module to body

*BA54.15-P-1003-01A

 Bolt of clamping bracket for fuse and relay module to suspension strut tower

*BA54.15-P-1005-01A

20

Take out BAS brake booster (A7/7)

 Installation:
Do not damage boot (9) during installation of BAS brake booster (A7/7).
To prevent leaks.

 Remove BAS brake booster (A7/7) from bulkhead and rotate by 45° counterclockwise.

 Pull fuse and relay box (F1) toward left when removing from BAS brake booster (A7/7).

 Installation: Install new seal (21).

21

Install in the reverse order

22

Bleed brake system

AR42.10-P-0010V

23

Connect STAR DIAGNOSIS, read out fault memory and erase if necessary



Check

 Warning

Risk of accident from vehicle starting off by itself when engine running. Risk of injury (bruises and burns) resulting from working on the engine while it is being started or when it is running.

Secure vehicle to prevent it from starting off by itself. Wear closed and snug-fitting work clothes. Do not touch hot or rotating parts.

AS00.00-Z-0005-01A

24

Check brake system for leaks

AR42.10-P-0100-01V

 Danger

Risk of death caused by limbs being caught or crushed by rotating parts when performing tests on the brake test stand

Never leave the vehicle unattended on the rollers except in an emergency. Ensure that no one is under the vehicle or near rotating parts during testing. In case of emergency, use the EMERGENCY OFF switch to shut down test stand.

AS42.00-Z-0001-01A

25

Carry out brake test on the test stand



AP42.00-P-4290BA

 Pneumatic brake booster

Number

Designation

Model 171

BA43.10-P-1002-01A

Nut, brake booster carrier to front end

Nm

20

 Fuse and relay box

Number

Designation

Model 171

BA54.15-P-1003-01A

Nut, fuse and relay module to body

Nm

6

 Fuse and relay box

Number

Designation

Model 171

BA54.15-P-1005-01A

Bolt of clamping bracket for fuse and relay module to suspension strut tower

Nm

6

 Windshield wiper

Number

Designation

Model 171

BA82.30-P-1004-01A

Nut on wiper arm

Nm

19