Brake Master Cylinder

Brake Master Cylinder

Special tools, testers and auxiliary items required

• Brake filler/bleeder unit (VAS 5234)

• The brake master cylinder cannot be serviced. If malfunctioning, replace entire unit.

Removing

- Remove plenum chamber cover.

- Remove engine compartment seal and cover strip in area of brake booster.

- Remove facing wall of plenum chamber.

- Place sufficient lint-free cloths in plenum chamber in the area of the brake master cylinder.

- Extract as much brake fluid as possible from the brake fluid reservoir using (VAS 5234).

- Disconnect connector off float warning indicator sensor.

- On vehicles with manual transmission, disconnect clutch master cylinder supply hose and seal with plug.

- Remove brake fluid reservoir, press the engagement straps toward outside at reservoir and simultaneously pull brake fluid reservoir out of sealing plugs.

- Remove left front brake line from retainer on master brake cylinder.

- Disconnect brake lines from master brake cylinder and seal brake lines using Sealing Plugs (1H0 698 311 A) from repair kit.

- Remove nuts from brake master cylinder.

- Carefully take brake master cylinder out of brake booster.

Installing

- Installation is performed in the reverse sequence.

Observe the following points when installing:

- When installing together the brake master cylinder and brake booster, make sure that the push rod is correctly located in the brake master cylinder.

• O-ring between master brake cylinder and brake booster is present.

• Always use new nuts.

- Bleed brake system. Refer to => [ Brake System, Bleeding ] Service and Repair

After bleeding brake system, basic setting for brake pressure sensor 1 (G201) must be performed.

Vehicle Diagnostic Tester, connecting and selecting functions, refer to => [ Vehicle Diagnosis, Testing and Information System Connecting and Selection Functions ] Testing and Inspection.