Brake systems · Brakes – hydraulics · Bleeding brake system

Bleeding brake system with brake filling and bleeding equipment - VAS 5234-

Special tools and workshop equipment required

  • Brake filling and bleeding equipment - VAS 5234-
  • Tool set for brake bleeding - VAS 6564-

4.1.1 Pre-bleeding:

Carry out pre-bleeding:

  • if a chamber in the brake fluid reservoir in vehicles with EDL, EDL/TCS or EDL/TCS/ESP is completely empty. This occurs e.g. in the case of brake system leaks.
  • Connect brake filling and bleeding equipment - VAS 5234- or
    • V.A.G 1869-.

Bleeding sequence:

  • 1 Bleed front left and front right brake calipers simultaneously.
  • 2 Bleed rear left and rear right brake calipers simultaneously.
  • Leave bleeder valves open with brake fluid hoses connected until brake fluid free from air bubbles flows out.

Then hydraulic unit must be bled again via function “Basic setting” of tester -VAS 5051-.

Initiate basic setting (to bleed brake system):

Connecting -VAS 5051- and selecting functions ⇒ 3 Connecting -VAS 5051- and selecting functions

  • Then bleed brake system as normal.

4.1.2 Bleeding (normal):

Adhere strictly to work sequence when bleeding brake system.

  • Connect brake filling and bleeding equipment - VAS 5234- or
    • V.A.G 1869-.
  • Open bleeder valves in specified order and bleed wheel brake cylinders/brake calipers.
  • 1 Rear left wheel brake cylinder/ brake caliper
  • 2 Front left brake caliper
  • 3 Front right brake caliper
  • 4 Rear right wheel brake cylinder/ brake caliper

Use suitable bleeder hose. It must sit tightly on bleeder valve so that no air can enter brake system.

  • Leave bleeder valve of each brake caliper open with bleeder hose fitted until brake fluid discharges free of air bubbles.

4.1.3 Subsequent bleeding

Carry out subsequent bleeding when:

  • brake pedal travel is too long or so-called »soft brake pedal«

Subsequent bleeding requires the assistance of a second mechanic.

  • Depress brake pedal firmly and hold.
  • Open bleeder valve on wheel brake cylinder/brake caliper.
  • Fully depress brake pedal.
  • Close bleeder valve with pedal held down.
  • Release brake pedal slowly.

This bleed sequence must be carried out 5 times per brake caliper.

Bleeding sequence:

  • 1 Rear left wheel brake cylinder/ brake caliper
  • 2 Front left brake caliper
  • 3 Front right brake caliper
  • 4 Rear right wheel brake cylinder/ brake caliper

A road test must be carried out after the brakes have been bled. When doing this an ABS regulation must be performed at least once.