Removal and installation of the brake master cylinder and vacuum booster (Audi A4 B7)

1. Remove the storage compartment on the driver's side (see Chapter 11).

2. Turn the brake light D/W (1 in illustration 6.3) counterclockwise and remove it.

3. Using the T40024 device (see illustration 10.6 Chapter 6) separate the brake pedal from the brake booster.

4. Remove the gutter cover and place enough rags in it to absorb any leaking brake fluid.

5. Pump the brake fluid out of the reservoir.

6. Disconnect the connector (1 in the illustration) low brake fluid level sensor and pull out the vacuum hose (2).



7. Unscrew the bolt (1 in illustration 10.4 Chapter 6) of the reservoir mount, press down the locking tab and simultaneously pull the reservoir out of the cuffs. Set the reservoir aside.

8. Remove the nuts and separate the brake pipes (1 and 2 in the illustration) from the brake master cylinder. Seal the opened holes with suitable plugs and place a rag in the hydraulic modulator area to collect the leaking brake fluid.





9. Separate the brake pipes (1 in the illustration) from the hydraulic modulator and remove them together with the rubber seal.



10. Remove the bolts (1 in the illustration) and remove the vacuum booster together with the master cylinder. If there is an upper front suspension strut, the strut must be removed (see Chapter 10).



11. If necessary, give away the nuts (1 in the illustration) mount the master cylinder and remove it from the vacuum booster.





12. Installation is carried out in the reverse order of dismantling the components. When installing the brake master cylinder on the vacuum booster, make sure that its rod is correctly positioned in the brake master cylinder. The hinge should be at a distance (and in the illustration) - 159±0.5 mm from the surface (1, without gasket).



13. After installation, adjust the brake light sensor (see Section 10) and bleed the brake hydraulic system (see Chapter 1).

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