Audi Workshop Service and Repair Manuals

Removing and installing hydraulic control unit Special tools and workshop equipment required

t  Brake pedal actuator -V.A.G 1869/2-

Sealing plug repair kit, Part no. 1H0 698 311 A

Fitting location: The hydraulic control unit is fitted on the left-hand side of the engine compartment. Removing   WARNING Do not bend the brake lines. –  Note or request radio code on vehicles with coded radio if necessary. –  Disconnect battery → Rep. Gr.27

–  Release connector from control unit in direction of arrow and unplug. –  Insert brake pedal actuator -V.A.G 1869/2- between brake pedal and driver's seat. Depress the brake pedal at least 60 mm. The brake pedal actuator -V.A.G 1869/2- must remain in position until all brake pipes have been reconnected to the hydraulic unit.   Note Cover the engine compartment to ensure that no brake fluid flows into it. –  Disconnect brake lines from hydraulic unit.

–  Loosen securing bolt - 1 - and pull the coolant expansion tank out in direction of arrow, then swivel tank to one side. –  Tightening torque: 6 Nm

–  Seal brake lines and tapped holes with plugs from repair kit Part No. 1H0 698 311 A.   Note Protect plenum chamber and engine compartment against any escaping brake fluid. –  Unscrew lines -1-, -2- and -3-.   Note On vehicles from model year 2002 a flexible hose has been fitted as part of the brake pipes; on vehicles built before MY2002 the brake lines have to be disconnected at the brake servo.

–  Unscrew brake lines -1- and -2- and seal with sealing plugs from repair kit, Part No. 1H0 698 311 A.

–  Detach connectors -1-. –  Unclip brake lines from bracket -2-.

–  Release retaining clip from below -1- and pull it out in direction of arrow. –  Remove hydraulic control unit. Installing When installing, note the following points in particular: t  Do not remove sealing plugs from new hydraulic control unit until corresponding brake line is to be fitted. t  If sealing plugs are removed from hydraulic unit sooner, brake fluid may escape and it may no longer be possible to fill and bleed the unit properly. –  Bleed brake system. –  Enter radio code. –  Connect battery. → Rep. Gr.27 Tightening torques

Component		Nm
Brake lines to hydraulic unit M10 (brake line diameter 5 mm)		12
Brake lines to hydraulic unit M12 (brake line diameter 5 mm)		12
Brake lines to hydraulic unit M12 (brake line diameter 8 mm)		20