Remove/install brake booster

AR43.10-P-0350FR

Remove/install brake booster

06.03.2020

Model

257

Model

290

Modification notes

20.04.2018

Screw/bolt, upper struts to suspension strut tower mounting bracket

Model 257

BA62.30-P-1001-02K

Shown on model 257

1

Nut

9

Electrical connector

2

Bolts

10

Strut

3

Strut

11

Electrical connector

4

Cap

12

Brake line

5

Brake fluid reservoir

13

Vacuum line

6

Master brake cylinder

A7/7

BAS brake booster

7

Nuts

K40/8

Engine fuse and relay module

8

Screw

14

Nut

15

Guide pin

16

Brake pedal

 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

Notes on safety-relevant components

AH00.00-Z-0019-01A

 

Remove/install

1

Reduce vacuum in BAS brake booster (A7/7) by operating the brake pedal (16) several times.

2

Remove left and right wiper arm.

AR82.30-P-6100FR

3

Remove air/water duct on driver's side.

4

Remove air/water duct on front passenger side.

5

Remove air/water duct under the wiper arms.

6

Remove strut (10).

Topical note

Notes on threaded connections fastened using a tightening angle-based tightening process

AH00.00-P-0020-01A

 Nut, upper struts to firewall

*BA62.30-P-1002-02K

 Screw/bolt, upper struts to suspension strut tower mounting bracket

*BA62.30-P-1001-02K

7

Remove screws (2, 8) and take off strut (3).

 Screw/bolt, lower strut to firewall

*BA62.30-P-1004-02K

 Screw/bolt, lower strut to suspension strut tower mounting bracket

*BA62.30-P-1003-02K

8

Cover painted surfaces in the repair area.


Protect painted surfaces from brake fluid.
Damage can otherwise be caused by escaping brake fluid.

9

Clean area around the cap (4) on brake fluid reservoir (5).


Before opening, clean area around the cap (4) thoroughly.
Otherwise dirt particles in the hydraulic component parts can result in malfunctions and total failure of the brake system.

Assembly cleaner

*BR00.45-Z-1028-04A

10

Unscrew cap (4) and remove sieve from brake fluid reservoir (5).

11

Extract brake fluid from brake fluid reservoir (5).

12

Seal brake fluid reservoir (5).

13

Disconnect electrical connector (9) from brake fluid level switch.

14

Unscrew nuts (7) and place engine fuse and relay module (K40/8) with connected lines to one side.

15

Clean master brake cylinder (6) in the area of the connections of the brake lines (12).


Thoroughly clean area around connecting points before opening the brake system.
Otherwise minute dirt particles in the hydraulic component parts can result in malfunctions and total failure of the brake system.

 Do not use any compressed-air for cleaning when the brake system is open.
Use clean, lint-free rag only.

Assembly cleaner

*BR00.45-Z-1028-04A

16

Remove brake lines (12) from master brake cylinder (6).

Note on calculation of tightening torque when using insertion or socket tools with various effective lengths

AH00.00-P-0015-01CW

 Retaining screw, brake line to master brake cylinder

*BA42.10-P-1003-04P

 Box wrench bit

*000589750300

17

Seal connection fittings on master brake cylinder (6) and brake lines (12).

 Record plug

*129589009100

18

Pull vacuum line (13) out of BAS brake booster (A7/7).

19

Disconnect electrical connector (11) from brake vacuum sensor.

20

Remove trim under instrument panel on driver's side.

AR68.10-P-1501FR

21

Remove guide pin (15) from brake pedal (16).

 Brake booster to brake pedal

*BA43.10-P-1002-01J

22

Unscrew nuts (14) of BAS brake booster (A7/7).

 Nut, brake booster carrier to front end

*BA43.10-P-1001-01J

23

Push brake lines (12) carefully to one side and remove BAS brake booster (A7/7) from engine compartment.


Do not deform the brake lines (12).
Otherwise the brake system may malfunction.


Do not damage boot during removal/installation of BAS brake booster (A7/7).
Otherwise the BAS brake booster (A7/7) may malfunction.

24

Remove master brake cylinder (6).

When replacing the BAS brake booster (A7/7).

AR42.10-P-0300FR

25

Install in the reverse order.

26

Bleed brake system.

AR42.10-P-0010FR



Check

27

Perform brake test on test stand.



AP42.00-P-4290BA

 Brake lines, brake hoses

Number

Designation

Model 257

Model 290.658/659/661 except code B07/U69

BA42.10-P-1003-04P

Retaining screw, brake line to master brake cylinder

Nm

16

16

 Brake lines, brake hoses

Number

Designation

Model 290.658/659/661 with code B07/U69,
model 290.679/688/689

BA42.10-P-1003-04P

Retaining screw, brake line to master brake cylinder

Nm

16

 Pneumatic brake booster

Number

Designation

Model 257

Model 290

BA43.10-P-1001-01J

Nut, brake booster carrier to front end

Nm

22

22

 Pneumatic brake booster

Number

Designation

Model 257

Model 290

BA43.10-P-1002-01J

Brake booster to brake pedal

Nm

22

22

 Frond end with front reinforcement

Number

Designation

Model 257

Model 290

BA62.30-P-1001-02K

Screw/bolt, upper struts to suspension strut tower mounting bracket

Stage 1

Nm

35

35

Stage 2

Nm

50

50

Stage 3

Loosen

°

180

180

Stage 4

Nm

50

50

 Frond end with front reinforcement

Number

Designation

Model 257

Model 290

BA62.30-P-1002-02K

Nut, upper struts to firewall

Nm

35

23

 Frond end with front reinforcement

Number

Designation

Model 257

Model 290

BA62.30-P-1003-02K

Screw/bolt, lower strut to suspension strut tower mounting bracket

Nm

50

50

 Frond end with front reinforcement

Number

Designation

Model 257

Model 290

BA62.30-P-1004-02K

Screw/bolt, lower strut to firewall

Nm

23

23

Repair materials

Number

Designation

Order number

BR00.45-Z-1028-04A

Assembly cleaner

A 000 986 56 01