Removing and installing brake master cylinder with brake servo — AUDI
Removing and installing brake master cylinder with brake servo on Audi: factory workshop procedure. Full factory text, tools and checks.
Workshop procedure for AUDI — the factory write-up, straight from real workshop data.
📋 Procedure
Audi
Audi A4
2001
Audi A4 Cabriolet
2003
Running gear
Brake system
Edition
04.2013
Removing and installing brake master cylinder with brake servo
Special tools and workshop equipment required
Release tool
T40024
Sealing plug repair kit, Part no. 1H0 698 311 A
Removing (repair group 68).
Turn brake light switch (1)
45° in anti-clockwise direction and remove.
Use release tool
T40024 to separate brake pedal from brake servo.
Extracting brake fluid with upgrade kit and extraction unit
V.A.G 1869/4 or brake filling and bleeding equipment
VAS 5234
Detach plenum chamber cover.
Lay out sufficient number of lint-free cloths in the area of the plenum chamber.
Open brake fluid reservoir.
Draw off brake fluid.
Unplug connector from sender for float warning indicator (1).
Pull off vacuum hose (2).
Unscrew securing bolt (1) for brake fluid reservoir.
Note
Protect the plenum chamber against any brake fluid which escapes.
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.
Detach brake fluid reservoir and lay it to one side.
Unscrew brake lines (1) and (2) and seal with sealing plugs from repair kit, Part No. 1H0 698 311 A.
Lay out sufficient number of lint-free cloths in the area of the hydraulic control unit.
Unscrew brake lines (1) and (2) and remove together with rubber grommet.
Unscrew securing bolts for brake servo (1) (Torx
T45).
Remove brake servo with brake master cylinder.
On vehicles fitted with cross piece the cross piece must be removed. (repair group 40).
Unscrew securing nuts (1) for brake master cylinder.
Carefully remove brake master cylinder from brake servo.
Installing
When installing, note the following points in particular:
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.
Bleed brake system (see the separate procedure).
TorqFix answers live for your specific car — tell it the engine code and it serves the matching sequence, torque figures and wiring for that exact variant.
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Who makes these pages, and how
TorqFix was built by a mechanic — after a 2,700 km drive with five roadside repairs that no diagnostic tool could explain.
The figures on this page come from manufacturer workshop documentation and are shown as they are. The page is assembled automatically from that data — it is not written by an AI. The AI works in the chat, where it answers for your specific car. It writes nothing here.
Variants of the same model differ. Cross-check torque against the factory manual for your engine before final tightening.
Seen a figure that does not match your manual? Write to us — we correct it and note when. support@torqfix.com
The story behind TorqFix → · How these pages are made →Workshop data on this page last updated 20 Sep 2026.