Hydraulic System, Pre-Bleeding

Hydraulic System, Pre-Bleeding

Description covers bleeding of hydraulic system using the brake charger/bleeder unit (VAS 5234).

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

Special tools, testers and auxiliary items required

• Brake Charger/Bleeder Unit (VAS 5234)

• Tool Set for Brake Bleeding (VAS 6564)

Perform Pre-Bleeding

• One chamber in the brake fluid reservoir is completely empty on a vehicle with EDL, EDL/ASR or EDL/ASR/ESP. This will happen if there are leaks in the brake system.

- Connect the (VAS 5234).

Bleeding sequence:

1 - Bleed the left front and right front brake caliper together simultaneously.






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






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

Then hydraulic unit must be bled once more via function "Basic setting" using vehicle diagnostic tester.

Initiate basic setting (to bleed the brake system):

Vehicle diagnostic tester, connecting and selecting functions. Refer to => [ Vehicle Diagnosis, Testing and Information System ] Testing and Inspection.

- Then, brake system must be bled normally