34 51 525 Removing and installing or replacing ABS/ASC+T, DSC1, DSC2, DSC3 hydraulic unit up to 09/98

NOTE: Note "General Information", Refer to 34 00... GENERAL DATA

CAUTION: After finishing work:
Check function of hydraulic control unit.

Installation:

Switch off ignition.

Disconnect battery negative lead.

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

Fig 1: Drawing Brake Fluid Out Of Expansion Tank With Suction Bottle

Unlock central connector (1) and pull off.

Unfasten nut (2) and remove ground wire.

Fig 2: Identifying Central Connector & Removing Ground Wire Nut

NOTE: Keep brake fluid out of cable connector.

Unfasten brake lines (1 - 7) at hydraulic control unit.

CAUTION: Do not mix up brake lines, mark before removing if necessary.

Installation:

Line connections
(F) 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 1 Diaphragm flow damper

Fig 3: Identifying Line Connections

Tightening torque. Refer to BRAKES - TIGHTENING TORQUES .

NOTE: Note installation position of diaphragm flow damper. The pin must engage in the bore.

Installation:

Note tightening torque. Refer to BRAKES - TIGHTENING TORQUES .

Fig 4: Identifying Pin Of Damper Engaging In Door

Unfasten screw and remove hydraulic control unit.

Fig 5: Unfastening Screw & Removing Hydraulic Control Unit