B. Replacement of SBC Hydraulic Unit

WARNING!
Risk of injury caused by body parts being pinched 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

Risk of poisoning from swallowing brake fluid.

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

1. Deactivate SBC system using Star Diagnosis (DAS).





2. Remove intake duct (arrow, Figure 2) on right side of engine.

Note:
For models with 12 cylinder engines also remove right air cleaner, refer to WIS: AR09.10-P-1150LA.








3. Disconnect SBC hydraulic unit harness connector (arrow, Figure 2a) from SBC hydraulic unit (A) and remove cable tie (B, Figure 3).

4. Detach the SBC hydraulic unit ground wire harness (arrow, Figure 3) at ground terminal stud (A).

5. Position SBC harness connector (arrow, Figure 2a) away from SBC hydraulic lines to prevent brake fluid from dripping on SBC harness connector and SBC wiring harness.





6. Remove omega (arrows, Figure 4) hose clips from SBC hydraulic unit bracket (A).

7. Remove SBC hydraulic unit refer to WIS: AR42.46-P-0010R steps 1 - 3, 5 - 14.

8. Inspect which version of the suction hose is installed on the SBC hydraulic pump:





^ If new version (rubber) hose (arrow, Figure 5) is installed, skip ahead to step 10.





^ If previous version (braided) hose (arrow, Figure 6) is installed, proceed to step 9 to replace the suction hose.





9. Replace suction hose (A, Figure 7):

^ Open the suction hose mounting clip (arrow) and remove suction hose (A) from bracket. Remove mounting clip (arrow) from threaded stud and discard.





^ Remove hose clamp (A, Figure 8) then remove suction hose (arrow) from suction line (B) using a plastic wedge (Example: Special Tool: W110 589 03 59 00).

CAUTION!
^ Do not use sharp-edged tools (e.g., screwdriver) to remove suction hose (arrows, Figure 8) from suction line (B), as this may cause damage to the SBC brake system.

Note:
^ When removing suction hose (arrow), do not bend suction line (B).

^ To prevent brake fluid from running out and to prevent contamination in the brake system, the suction hose (arrows, Figure 8) and line (B) are to be plugged using suitable plugs from the stop plug kit (Special Tool: W129 589 00 91 00).

^ Discard old suction hose (arrow) and clamp (A) after removal.





^ Verify that the dimension X (Figure 9) on the new SBC suction hose (A) equals 20 cm. Adjust (if necessary) by repositioning the mounting clip (B) on the SBC suction hose (A).

^ Place new hose clamp onto unmarked side of suction hose (C, Figure 9).





^ Connect the unmarked end of the suction hose (C, Figure 9) onto the suction line (A, Figure 10) and secure hose with a new hose clamp (arrow, Figure 10).





^ Install the new SBC suction hose mounting clip (arrow, Figure 11) onto the mounting stud.

Note:
To gain better access to mounting clip (during installation); remove the plastic cover over the right head lamp; then tap the clip into place using a socket extension and plastic mallet.





10. Remove cable tie (left arrow, Figure 12) securing ground wires (A) to SBC connector housing (B).

11. Remove cable tie (right arrow, Figure 12) securing SBC wire harness (C) to SBC connector housing (B).





12. Remove SBC connector housing cover (A, Figure 13):

^ Using a small screw driver, carefully pry cover (A) away from locking lugs (arrows) until cover (A) disengages.

^ Repeat the process on opposite side.

^ Remove the cover (A) from the housing (B).





Note:
There are two different versions of the SBC wiring harness connector (Figures 14 a, b) installed in vehicles involved with this campaign.





13. Open the (gray) secondary lock in the SBC connector housing (A, Figure 15) by sliding the lock in the direction indicated by the arrows (Figure 15) using a small screwdriver.





14. Remove SBC ground wires (arrows, Figure 17) from SBC harness connector (A):

^ Unpin SBC ground wire connectors (position 37 and 44) using cable release (Special Tools: W 000 589 13 99 30 and W 220 589 01 99 50) and remove ground wires (arrows) from SBC connector housing (A).

^ Discard old ground wire harness, it is no longer needed.

15. Insert the new ground wire harness (arrows Figure 17) into the SBC connector housing (A):

^ Insert longer ground wire into position 44.

^ Insert shorter ground wire into position 37.

Note:
Ensure ground wire connectors are properly locked into place.





16. Close the (gray) secondary lock of the SBC connector housing (A, Figure 18) by sliding the lock in the direction indicated by the arrows (Figure 18) using a small screwdriver until it locks into place.

17. Reinstall connector cover (A, Figure 13) in reverse order.





18. Secure SBC wiring harness (A, Figure 19) (excluding ground wires) to the SBC connector cover receptacle (arrow) using a new cable tie (B).

Note:
^ Ensure that the SBC wiring harness (A) is properly routed so that it is free of tension in the SBC connector housing.

^ The cable tie "buckle" (D) must be located at the side of the connector cover receptacle (arrow) as depicted.

19. Secure ground wiring harness (C) to the SBC connector housing receptacle (F) using a new cable tie (E).

20. Attach SBC harness mounting bracket to the SBC hydraulic unit:








^ Using hand tools, tap threads into SBC hydraulic unit bores (arrows, Figure 21) by running self tapping screw (arrow, Figure 20) into lower bore without mounting bracket positioned on SBC unit.

Note:
^ In order to avoid breaking the self-tapping screw (arrow) during installation, the screw (arrow) must be positioned absolutely straight

^ Do not use power tools to install self tapping screw.

^ In the event self tapping screw (arrow, Figure 20) is broken during installation of bracket (A) perform step 21 then continue with campaign (installation of bracket due to breakage of mounting screw will not be covered under warranty).

^ Remove self tapping screw (arrow).

^ Position bracket (A) on SBC hydraulic unit, reinstall self tapping screw (arrow) and torque to 7 Nm.





21. Install clamp-on mounting bracket (Figure 22) if necessary due to broken self tapping screw:

Note:
Ensure sheathing (arrow) on mounting bracket clamp is positioned as shown in Figure 22.





^ Position mounting bracket (B) onto SBC hydraulic unit (A) as shown in Figure 23.

Note:
^ Ensure mounting bracket (B, Figure 23) is flush with SBC hydraulic unit (A).

^ Torque mounting clamp screw (C) to 5 Nm while pressing bracket (B) onto SBC unit (A) (Proceed to step 24).

22. Install new SBC hydraulic unit into SBC body mounting grommets.

23. Connect hydraulic lines to SBC unit; refer also to WIS AR42.46-P-0010R steps 15-21.





24. Connect SBC suction hose (A, Figure 24) to SBC hydraulic unit fitting (B); refer also to WIS: AR42.46-P-0010R steps 15-21.

Note:
Ensure new hose clamp (arrow) is installed.





25. Secure new SBC suction hose (A, Figure 25) to SBC hydraulic unit mounting bracket (B) using new ("omega" type) mounting clips (arrows).

26. Insert a cable tie through slots (C, Figure 25) in bracket (D), do not close cable tie.

Note:
Cable tie installation is shown on "bolt-on" type mounting bracket, cable tie installation for clamp-on type mounting bracket is similar.





27. Connect SBC harness connector (A, Figure 27) to SBC hydraulic unit and secure by engaging locking mechanism.





28. Attach the ground wire harness ring connector (A, Figure 26) to the body ground terminal (B) with M6 nut. Torque the M6 nut to 10 Nm.

Note:
^ The ground wire harness (arrow) must be routed under the SBC suction hose (C). The ring connector (A) must be positioned as shown in Figure 26.

^ This ground terminal (B) is to be used only for mounting the SBC ground wire harness (arrow).

29. Complete the installation of the SBC hydraulic unit.

30. Check for leaks and bleed SBC system (refer to WIS: AR42.46-P-0010R), (Refer to SDS instructions).

Note (regarding above WIS instructions):
Disregard WIS notes regarding brake bleeder pressure. The maximum pressure for brake bleeder is 2.5 bar.

31. Connect SDS and check software release:

Note:
Ensure only the following versions of DAS are used:

^ 11/2005 with SBC patch 479 installed on SDS

^ Any DAS version after 11/2005

Navigate through the following menu items in DAS and follow on-screen instructions:

"Control units/Chassis/SBC - Sensotronic Brake Control/Control unit adaptations".

Note:
^ Ensure to follow the on-screen instructions in DAS for connecting programming and terminal inspection tool to the SBC hydraulic unit.

^ In the event of malfunctions during the SBC programming, a message will appear in the DAS display and a troubleshooting guide will be displayed.

^ In the event DAS indicates that the SBC hydraulic unit requires replacement after inspecting SBC connector terminals, refer to WIS: AR42.46-P-0010R (for replacement instructions).

Note (regarding above WIS instructions):
Disregard WIS notes regarding brake bleeder pressure. The maximum pressure for brake bleeder is 2.5 bar.

32. Secure SBC wiring harness (B, Figure 27) to SBC hydraulic unit bracket (C) with cable tie (arrow). Tighten cable tie (arrow) using Hellermann MK9 cable tie pliers (Special Tool W 352 589 02 37 00); use setting 3 on cable tie pliers.

Note
^ The cable tie buckle (D) must not touch the bracket (C).

^ When attaching SBC wire harness (B) to the bracket (C), ensure that the wire harness (B) touches the bracket (C) and is mounted there tension free.

^ After the SBC wire harness (B) is secured, it must not be able to move in the longitudinal direction toward the bracket.

CAUTION!
Ensure harness is properly mounted to allow cable strain relief in area between cable tie and connector.

33. Proceed to SUBJECT C - QUALITY ASSURANCE MEASURES.