Brake Proportioning/Combination Valve: Testing and Inspection

CHECKING OPERATION

Brake Pressure Regulator:

- Depress brake pedal once firmly (car must be on ground).
- Release pedal suddenly and check that lever on pressure regulator moves.

NOTE: It is normal if small quantities of brake fluid escape through vent hole. If in doubt, perform pressure/leakage test under pressure before adjusting regulator.

CHECKING PRESSURE

- Connect VAG 1310 or suitable gauge and bleed.
- Depress brake pedal until front axle pressure reads 100 bar (1450 psi), hold for 5 seconds.
^ Rear pressure reading must not vary more than 10 bar (145 psi) within 5 seconds.
^ If results cannot be obtained, replace brake pressure regulator.
- Remove pressure gauges.
- Bleed brakes.