Remove/install brake operating unit (BOU)

AR42.46-P-0020TX

Remove/install brake operating unit (BOU)

23.3.06

 

Remove/install

Danger!

Risk of injury caused by body parts being jammed or crushed. Risk of injury to skin and eyes caused by brake fluid spraying out at high pressure when working on the SBC brake system

Deactivate SBC brake system using STAR DIAGNOSIS.

AS42.46-Z-0001-01A

Danger!

Risk of poisoning caused by swallowing brake fluid. Risk of injury caused by brake fluid coming into contact with skin and eyes.

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

AS42.50-Z-0001-01A



Notes on repairs to brake system

AH42.00-P-0003-01A



Brake fluid notes

AH42.50-P-0001-01A

1

Deactivate SBC brake system using STAR DIAGNOSIS.

 The following steps should be run through in STAR DIAGNOSIS:

Select menu item "SBC-Sensotronic Brake Control"/"Deactivate 'SBC' system".

Then process all the individual steps from top to bottom.



Connect STAR DIAGNOSIS and read out fault memory

AD00.00-P-2000-04A

STAR DIAGNOSIS diagnosis system

*WH58.30-Z-1048-13A

2

Take off cover (1)

3

Disconnect electrical connector to the brake fluid indicator switch (S11)

4

Suction off brake fluid from the expansion reservoir (2)

 Installation: Check that the expansion reservoir (2) is seated correctly. No brake fluid may escape from the seals (6), otherwise the SBC system can malfunction.

5

Detach return line SBC (3) from expansion reservoir (2)

 Clean the area around the separation point thoroughly before opening the SBC system. Even minute particles of dirt, introduced into the hydraulic components, can result in malfunctions and a total failure of the SBC system.

6

Detach SBC feed line (4) from expansion reservoir (2)

 Collect escaping brake fluid using a lint free, absorbent rag and immediately seal connections using stop plugs.



*129589009100

7

Unscrew bolt (2a)



*BA42.46-P-1002-02B

8

Pull the expansion reservoir (2) out of the brake operating unit (BOU) (5)

 Check seals (6) for damage; replace if necessary.

 Installation: The gaskets (6) have no collar and, when assembling the expansion reservoir (2), can be pressed out of the brake operating unit (BOU) (5). Therefore, mount the expansion reservoir (2) vertically on the brake operating unit (BOU) (5) and simultaneously press into the front and rear seal (6).

9

Disconnect electrical connector on SBC pedal value sensor (B37/1)

10

Detach the brake lines (7) from the Brake Operating Unit BOU (5)

 Collect brake fluid which flows out with a non-fluffing, absorbent cloth. Seal connections immediately.



*BA42.46-P-1003-02B



*BA42.46-P-1004-02B



*000589770300



*129589009100

11

Remove left cover below instrument panel

AR68.10-P-1500TX

12

Remove stop lamp switch (S9/1)

AR42.10-P-0040TX

13

Remove clutch pedal switch (S40/3)

 Press the locking catch and turn the clutch pedal switch (S40/3) clockwise through 90°.

14

Unclip cover (8) on brake pedal

15

Remove stud (9) from brake pedal

16

Unscrew nut (5a) from brake operating unit (BOU) (5)



*BA42.46-P-1001-02B

17

Remove brake operating unit (BOU) (5)

18

Install in the reverse order

19

Bleed brake system with STAR DIAGNOSIS

 When performing the bleeding operation, it is essential to observe the instructions in the document "Bleeding brake system using STAR DIAGNOSIS".

AR42.10-P-0012TX

 The following steps should be run through in STAR DIAGNOSIS:

Select menu item "commissioning after repair"/"exchange of brake operating unit (BOU)".

Then process all the individual steps from top to bottom.

Number

Designation

Model
219

BA42.46-P-1001-02B

Nut, BOU to firewall

Nm

20

BA42.46-P-1002-02B

Bolt expansion reservoir to brake operating unit (BOU)

Nm

5

BA42.46-P-1003-02B

Pressure connection, primary circuit

Nm

13

BA42.46-P-1004-02B

Pressure connection, secondary circuit

Nm

13

Number

Designation

WH58.30-Z-1048-13A

STAR DIAGNOSIS diagnosis system, Compact Passenger Car

6511 1801 00