Removing and Installing

Control module and hydraulic unit, removing and installing
Special tools and equipment





^ VAG1331 Torque wrench





^ VAG1869/2 Brake pedal depressor

Installation location:
The control module is bolted to the hydraulic unit and is located on the left side, in the engine compartment.

WARNING: Do not bend the brake lines in the area of the hydraulic unit!

Removing
^ Vehicles equipped with coded anti-theft radio, note or request radio code if necessary.
^ Disconnect battery.





^ Unscrew coolant expansion tank -2- and place to side with coolant hoses still connected.

Note: The hydraulic unit -1- is turned 180° on the W8.





^ Release control module connector in direction of arrow and pull off.
^ Disconnect connector from brake pressure sensor.
^ Insert VAG 1869/2 brake pedal depressor.
^ Depress brake pedal with brake pedal depressor.
^ Connect bleeder bottle hose to left-front brake caliper bleed screw and open bleed screw.
^ Close left-front bleeder screw.
^ Place lint-free cloths under the control module and hydraulic unit.

Make sure no brake fluid gets onto contacts.

^ Disconnect brake lines on the hydraulic unit.
^ Seal brake lines and threaded holes with plugs from repair kit Part No. 1 HO 698 311 A.





^ Unclip locking clips -1- from below and remove in direction of arrow.
^ Remove hydraulic unit with control module.

If the control module malfunctions, the hydraulic unit must be separated from the control module and the control module must be replaced, Refer to Antilock Brakes / Traction Control Systems, Description and Operation
If the hydraulic unit malfunctions, the complete hydraulic unit with control module must be replaced.

Installing

Note:
^ Remove sealing plugs on new hydraulic unit when the corresponding brake line is going to be connected.
^ If the sealing plugs are removed too early, brake fluid can escape, and can no longer be guaranteed that the unit is sufficiently filled or adequately bled.

^ Installation is the reverse order of removal.
^ Bleeding brake system, Refer to Brake Bleeding, Service and Repair
^ Enter radio code.
go to Code control module using VAS 5051 via "Guided fault finding" function.

Tightening torques:
Brake lines to ABS module:
Thread M 12 x 1, AF 11 14 Nm
Thread M 12 x 1, AF 12 24 Nm