Brake Bleeding: Service and Repair

Brake System, Bleeding

• Brake fluid must never come into contact with fluids containing mineral oils (oil, gas, cleaning solutions). Mineral oil damages the sealing plugs and boots of the brake system.

• Brake fluid is poisonous. NEVER siphon brake fluid with your mouth! Also due to its corrosive effect, brake fluid must not come into contact with paintwork.

• Brake fluid is hygroscopic, meaning that it absorbs moisture from the surrounding air, and must therefore be stored in air-tight containers.

• When bleeding, brake fluid that has been flushed through must not be reused and must be disposed of properly.

• Observe disposal regulations, refer to => [ Brake Fluid ] Description and Operation.

• Only use new brake fluid conforming to US-Norm FMVSS 116 DOT 4.

• Genuine VW/Audi brake fluid conforms to this specification.

• Do not use any silicone-based fluid.

• Avoid contaminating brake fluid with particles or lint (for example from cleaning cloths).

• Rinse off spills, by using plenty of water.

• Do not work with compressed air and do not move vehicle while the system is open.

• During the final road test, ensure that a ABS-controlled brake test is performed at least once (pulsation must be felt at the brake pedal).

• The brake system indicator light blinks when the brake fluid is too low or the ABS system or parking brake is malfunctioning.

Bleeding, with Electronic Stability Program

• There must be a positive pressure of 2 bar to bleed the hydraulic unit N55. Pressure setting must be checked at bleeder device.

• Only place brake pedal load device on brake system during assembly, then bleed.

Special tools, testers and auxiliary items required

• (VAS 5234) Brake Charger/Bleeder Unit

• (VAS 5234/1) Adapter

• Bleed the brake system with the brake charger/bleeder unit VAS 5234 with the adapter VAS 5234/1.

Follow the (VAS 5234) operating instructions.

- Remove the plenum chamber cover.

- Raise the vehicle.

- Connect the (VAS 5234) with (VAS 5234/1).

- Open the bleeder screws in the specified sequence and bleed (support with pedal pressure if necessary).

Bleeding Sequence

1 Left front brake caliper
2 Right front brake caliper
3 Left rear brake caliper
4 Right rear brake caliper.

- Bleed until brake fluid comes out with no bubbles and foam.

- Close the bleeder screws.

- Lower the vehicle.

- Install plenum chamber cover.