Hydraulic Control Assembly - Antilock Brakes: Service and Repair

Note: Refer to "General Data", found in Brakes and Traction Control, Description and Operation.

Before removing the hydraulic unit, read out the fault memory of the control unit and if necessary print the fault code.
After finishing work:
Check function of hydraulic control unit (refer to DIS, Diagnosis and Information System).

Installation:
Bleed brake system.





Draw brake fluid out of expansion tank with a suction bottle reserved for exclusive use with brake fluid.





Unlock fastener of plug connection (1) in direction (2). Vertically disconnect plug connection (1) in direction (3) upwards.

Installation:
Position plug connection (1) vertically on control module in order to avoid damaging pins.





Unfasten brake pipes.

Caution: Do not mix up brake pipes (mark if necessary before removal).

Installation:
Pipe connections
(V) from THZ circuit F to hydraulic control unit circuit F (front axle circuit)
(R) from THZ circuit R to hydraulic control unit circuit R (rear axle circuit)
(FR) from hydraulic control unit FR to front right wheel brake
(FL) from hydraulic control unit FL to front left wheel brake
(RR) from hydraulic control unit RR to rear right wheel brake
(RL) from hydraulic control unit RL to rear left wheel brake
Observe tightening torque, refer to Brakes, Specifications.

DSC
Unlock and disconnect plug connection (4) on pressure sensor.
Release screw (5) and remove hydraulic control unit; do not bend brake lines in doing so.