Brake Bleeding: Service and Repair

Brake System, Bleeding

• Description covers bleeding of brake system using the brake filler and bleeder tool (VAS 5234).

Only use new brake fluid conforming to VW standard (VW 501 14).

• Bleeding the braking system on vehicles with ABS is carried out as for vehicles with conventional braking systems.

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

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

• Brake fluid must never come into contact with fluids containing mineral oils (oil, gas, cleaning solutions). Oils containing minerals damage seals and sleeves on brake systems.

• Brake fluid is poisonous. Due to its caustic nature, it must also never be brought into contact with paint.

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

• Rinse off any leaking brake fluid using plenty of water.

• Do not reuse brake fluid once drained.

• Observe waste disposal regulations!

• A positive pressure of 2 bar required to bleed the ABS hydraulic unit (N55).

Special tools, testers and auxiliary items required

• Brake filler/bleeder unit (VAS 5234)

• Brake filler/bleeder unit suction adapter (V.A.G 1869/4)

• Tool set for brake bleeding (VAS 6564)

Pre-Bleeding

• On vehicles with ABS/ASR or ABS/EDS/ASR/ESP, the brake system must be pre-bled when a chamber in the brake fluid reservoir is completely empty.

Only use new brake fluid conforming to VW standard (VW 501 14).

- Connect the (VAS 5234).

Bleeding sequence:

1 - Bleed the left front and right front brake calipers simultaneously

2 - Bleed left rear and right rear brake caliper together simultaneously

- With bleeder bottle hoses attached, leave bleeder valves open long enough that brake fluid exits without bubbles.

- Afterward, bleed the brake system normally.

Bleeding, Normal

• Adhere strictly to work sequence when bleeding brake system.

Only use new brake fluid conforming to VW standard (VW 501 14).

- Connect the (VAS 5234).

- Open bleeder valves in the prescribed sequence and bleed brake caliper.

1- Front left brake caliper

2 - Right front brake caliper

3 - Left rear brake caliper

4 - Right rear brake caliper

• Use suitable bleeder hose. It must fit tightly on bleeder valve so that no air gets into brake system.

- With bleeder bottle hose attached, leave bleeder valve open long enough that brake fluid exits without bubbles.

Post-Bleeding

Only use new brake fluid conforming to VW standard (VW 501 14).

A second mechanic is required to assist:

A technician has to sit in the driver seat the entire time so that the brake pedal does not get twisted.

- Press brake pedal forcefully and hold.

- Open bleeder valve at brake caliper.

- Press brake pedal down onto stop.

- Close bleeder valve with the pedal assembly pressed.

- Release brake pedal slowly.

This bleeding procedure must be performed 5 times per brake caliper.

Bleeding sequence:

1- Front left brake caliper

2 - Right front brake caliper

3 - Left rear brake caliper

4 - Right rear brake caliper

• A road test must be performed after bleeding. During this, at least one ABS regulation must be performed!