Removing and installing brake master cylinder together with brake servo unit — AUDI

Special tools and workshop equipment required

Workshop Manual, General Body Assembly
Plug repair set, Part no. 1H0 698 311A
T10006

Removing

Remove storage compartment, driver's side.

=> General Body Assembly; Repair group 68
General Body Assembly

Releasing brake pedal

Ensure that the brake light switch is removed.

1 -
Inserting release tool
-T10006-
Feed the tool in from below.

2 -
Releasing process
Hold the brake pedal tight. Lift the catches off the ball head by a slight pull on the tool -arrow A-.
Hold the tool tensioned so that the catches do not engage again on the ball head.
Now, detach the brake pedal from the ball head -arrow B-.

Fit bleeder hose and bleeder bottle to the front left brake caliper bleeder screw and open bleeder screw.
Depress the brake pedal in order to pump out as much brake fluid as possible.
Close front left bleeder screw.

Unscrew the bolt -3- attaching the brake fluid reservoir.
Unplug the connector of the sender for the float warning indicator -2-.

Detach feed hose -1- for clutch master cylinder.

Notes:

Protect the plenum chamber against any escaping brake fluid.
The underside of the brake fluid reservoir clips into the brake master cylinder.

To remove reservoir, press down locking lug and at the same time pull brake fluid reservoir out of sealing plugs.
Remove brake fluid reservoir.

Detach brake pipes -3- and seal with the dummy plugs from repair kit Part No. 1H0 698 311 A.
Disconnect vacuum hose -2-.
Unscrew the bolts attaching the brake servo unit -1- (Torx T45).
Remove brake servo with brake master cylinder.

Unscrew the nuts attaching the brake master cylinder -1-.
Carefully remove brake master cylinder from brake servo unit.

Pay special attention to the following on installation:

Before installing brake master cylinder, clean any residual brake fluid off plenum chamber.
When assembling brake master cylinder with brake servo unit, make sure push rod is properly positioned in brake master cylinder.

Adjust brake light switch =>Page
45-45
.
Adjusting vent valve for cruise control system => Page
46-110

Bleeding clutch hydraulic system:

Connect V.A.G 1869 but do not switch on yet.
Open bleeder screw on slave cylinder.
Attach collector bottle hose.
Switch on the bleeding appliance and allow about 100 cm3 of brake fluid to flow out of the clutch slave cylinder.
Close bleed screw.
Bleed brake system => Page
47-46