Checking For Leaks

WARNING: This page does not describe the selected car, but rather 18 other vehicles, including the 2016 Audi S4, 2016 Audi A4 Quattro, 2016 Audi A4, 2015 Audi S4, and 2015 Audi A4 Quattro. However, it is still accessible from the selected car via links, so may be relevant.

NOTE:

The hydraulic brake system must be bled.

Only install genuine parts or components approved by Audi in the brake system.

The if the brake fluid replacement interval specified by Audi is exceeded, replace the brake fluid.

Check the system visually for leaks.

Fix leaks and remove dirt on the hydraulic system.

-- Switch the engine off.

-- Press the brake pedal until there is no more brake assistance - "pump the brake booster empty". The brake pedal becomes hard.

-- Press the brake pedal about 20 mm out of the resting position.

-- Hold the force on the pedal steady for about 20 seconds.

The brake pedal travel must not increase.

-- Release the brake pedal.

-- Press firmly on the brake.

-- Hold the force on the pedal steady for about 20 seconds.

The brake pedal travel must not increase.

If the pedal sinks down during one of the tests, repeat the visual inspection on the brake system.

If no leaks are found, the brake master cylinder is probably has leaks and must be replaced.

CAUTION:

Brake fluid must not run into the brake booster when replacing the brake master cylinder.