Hydraulic System, Bleeding With Brake Charger/Bleeding Unit

Special tools and workshop equipment required 

• Brake Charger/Bleeder Unit:VAS5234  with Brake Bleeder Adapter :VAS5234/1A 
• or
• Brake Filling and Bleeding Equipment:VAS6860 
• Read the operation information for Brake Charger/Bleeder Unit:VAS5234  or Brake Filling and Bleeding Equipment:VAS6860  .
• Wrench - Brake Bleeder Set:VAS5519 
• Brake Bleeding Tool Set:VAS6564 

• The brake system is divided by the axle on this vehicle.
• Right and left front axle
• Right and left rear axle
• The bleeding of the hydraulic system using the :VAS5234  is described.
• An initial pressure of 2 bar (29 psi) is required to bleed the ABS Hydraulic Unit -N55-.

Procedure

• Wheels are removed. Refer to WHEELS AND TIRES .

-- Open the access cover.

TIP:

Make sure that the brake fluid reservoir is always filled, but not over the "MAX" mark.

-- Fill the brake fluid reservoir up to the "MAX" mark.

Fig 1: Brake Fluid Reservoir

Courtesy of AUDI

-- Connect the :VAS6860  .

Courtesy of AUDI

-- Attach the :VAS5234/1A  to the brake fluid reservoir.

-- Adjust the pressure direction on the :VAS5234  . Refer to the :VAS5234  Service Information.

or

-- Adjust the pressure direction on the :VAS6860  . Refer to the :VAS6860  Service Information.

-- Remove the protective cap -3- from the bleed screw -1- on the respective brake caliper.

Fig 2: Identifying Protective Cap, Bleed Screw And Container Bleeder Hose

Courtesy of AUDI

-- Connect the bleeder bottle hose -2- as shown.

TIP:

Use a suitable bleeder hose. It must be seated tightly on the bleed screw so that no air can enter the brake system.

The front brake calipers each have two bleed screws.

Bleed the brake caliper at each bleed screw.

Bleeding Sequence

1. Outer Left Front Brake Caliper
2. Left front inner brake caliper
3. Outer Right Front Brake Caliper
4. Right front inner brake caliper
5. Left Rear Brake Caliper
6. Right Rear Brake Caliper

TIP:

Bleed the brake caliper at each bleed screw. If the brake caliper has two bleed screws, bleed the outer screw first.

-- Leave the bleed screw open with the brake fluid hose connected, until brake fluid flows out clear and without air bubbles.

-- Press brake pedal five times to assist the bleeding procedure.

-- Tighten the bleed screw, remove the bleeder hose and place the dust cap on the bleed screw.

-- Repeat the bleeding procedure in the specified sequence for the remaining brake calipers.

-- Fill the brake fluid reservoir up to the "MAX" mark and tighten the cap.

Fig 3: Brake Fluid Reservoir

Courtesy of AUDI

• Do not add brake fluid above the "MAX" mark otherwise it will leak out of the reservoir.

-- Start the engine and check the brake pedal travel and pressure.

-- If the pedal travel is too long, check the brake system for leaks or repeat the bleeding procedure.

• A road test must be performed after bleeding. While doing so, at least one ABS control must be performed at all four wheels.

Changing the brake fluid

Refer to BRAKE FLUID, CHANGING .

Tightening Specifications:

Front brake caliper bleed screw: 18 Nm.

Rear brake caliper bleed screw: 11 Nm.

Changing the brake fluid

Refer to BRAKE FLUID, CHANGING .

Tightening Specifications

• Refer to OVERVIEW - FRONT BRAKES
• Refer to OVERVIEW - REAR BRAKES