Vacuum Brake Booster: Service and Repair

Brake Booster

Special tools, testers and auxiliary items required

• Brake Filler/Bleeder Unit (VAS 5234) Or

• Brake Filler/Bleeder Unit (V.A.G 1869)

• Brake Filler/Bleeder Unit Suction Adapter (V.A.G 1869/4)

• Repair Kit Plugs (1H0 698 311 A)

- Remove cover on the driver side.

- move adjustable steering column all the way back (opposite direction of travel)

- Disconnect brake light switch - 2 - and remove, see => [ Brake Light Switch ] Service and Repair.





- Disconnect brake pedal from brake booster. Refer to => [ Brake Booster ] Service and Repair

- Remove plenum chamber cover





- Remove multi-point socket head bolts - 1 - and - 3 -, tightening specification 25 Nm.





- Remove tower brace - 2 -.

- Remove wiper arms.

- Remove rear plenum chamber cover.

- Open brake fluid reservoir.





- To protect against escaping brake fluid, place a lint-free rag in the area under the brake master cylinder.

- Draw off as much brake fluid as possible from brake fluid reservoir using Brake Charger/Bleeder Unit Suction Adapter (V.A.G 1869/4) or Brake Charger/Bleeder Unit (VAS 5234).





- Remove brake fluid reservoir locking bolt - 1 -.

- Disconnect connector - 2 -





• Protect plenum chamber from escaping brake fluid.

- Brake line, removing

- To remove reservoir, press locking tab down and at the same time, remove brake fluid reservoir from sealing plugs.

- Completely detach brake lines - 1 - and - 2 - from brake master cylinder and hydraulic assembly, seal with plugs and remove.





- Remove brake booster bolts - 2 -.

- Remove vacuum line - 3 -.





• Make sure that no contamination enters vacuum opening.

- Remove brake booster with brake master cylinder.

- Remove brake master cylinder nut - 1 -.





- Carefully take brake master cylinder out of brake booster.

Installing

When installing, observe the following:

• Before installing brake booster, clean plenum chamber of remaining escaping brake fluid.

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

Brake Pedal and Brake Booster, Connecting

- Hold ball head of push rod in front of mounting and push brake pedal in direction of brake booster, so the ball head locates audibly.

- Adjust brake light switch. Refer to => [ Brake Light Switch ] Service and Repair.

- Bleed brake system. Refer to => [ Bleeding Brake System ] Procedures.