Bleeding the brake system (Audi 80 B3)

After each brake repair, during which the system was opened, there may be air in the pipes. Then the air should be removed from the brake system. The presence of air is manifested by the softness of the brake pedal when it is pressed. In this case, the cause of the leak should be eliminated and the air should be removed from the system.

Removing air from the brake system is done by bleeding the brake pedal, which requires an assistant.

If the entire system needs to be bled, the air is bled from each wheel brake. This occurs when air enters each individual brake cylinder. If only one caliper has been replaced or repaired, it is usually sufficient to bleed the corresponding brake cylinder.

Air removal sequence:

• 1. Brake master cylinder air release valves (if any).
• 2. Rear right brake caliper or cylinder.
• 3. Rear left brake caliper or cylinder.
• 4. Front right brake caliper
• 5. Front left brake caliper.

Remove the cap from the brake cylinder air bleeder valve. Clean the valve, connect a clean hose, and lower the other end of the hose into a bottle half filled with brake fluid (a suitable hose and a suitable vessel are available in auto parts stores).

The assistant should press the brake pedal several times until pressure is created in the brake system. This will be felt by the increased resistance when pressing the pedal.

When the pressure is reached, press the pedal without removing your foot from the pedal.

Open the brake caliper air release valve with a key by about half a turn. The brake fluid will flow into the bottle. Make sure that the end of the hose in the bottle is always inside the fluid.



Once the fluid pressure drops, close the air release valve.

Repeat the pumping process until pressure is created. Keep your foot on the pedal. Open the air release valve until the pressure drops. Close the valve.

Continue the process of removing air from the brake cylinder until no more air bubbles are released from the liquid flowing into the bottle.

After removing the air, remove the hose and put the cap on the valve.

Remove air from the remaining wheels in the same way. Follow the sequence of actions.

Note: When bleeding air, occasionally look at the brake fluid reservoir. The fluid level should not drop too much, otherwise air will be sucked in through the reservoir. Top up with new brake fluid!

After removing the air, the tank should be filled to the MAX mark.

This publication is borrowed from the resource audimanual