Hydraulic System: Testing and Inspection

Checking service brake high- and low-pressure tests

Caution: The high- and low-pressure tests (leak checks) must be carried out only when the engine is switched off.





High-pressure test (leak check):

Perform test on both brake circuits.

1st brake circuit, front axle

2nd brake circuit, rear axle

Unscrew vent plug, connect pressure tester and vent.





Load brake pedal with approx 500 N of force and block brake pedal with pedal support. After 2 minutes, pressure must not drop by more than 8%.

Low-pressure test:





Perform test on both brake circuits.

Reset pedal support until test pressure in brake system is equivalent to 2 to 5 bar.

Car and measuring equipment must remain perfectly still as vibrations will distort the result.

Pressure should remain constant during five-minute test.

Check all rubber parts in case of excessive pressure drop.

Bleed brake calipers and wheel brake cylinders after finishing test.