Checking Service Brake: High and Low Pressure Tests

34 00 519 Checking service brake: high- and low pressure tests

Important: The high/low-pressure test (leakage test) must be carried out with the engine switched off.

Observe safety instructions on raising the vehicle.

High-pressure test (leakage test):
Perform test on both brake circuits.
1st brake circuit, front axle
2nd brake circuit, rear axle
Remove bleeder screw, connect pressure tester and bleed.





Load brake pedal with a force and block brake pedal with pedal support, refer to Technical Data.
After 2 minutes, pressure is permitted to drop by max. 8%.





Low-pressure test:
Perform test on both brake circuits.
Reset pedal support until test pressure in braking system is 2 5 bar.





Vehicle and measuring apparatus must remain steady as vibrations will distort the result.
Pressure must remain constant for a test period of 5 minutes.
Check all rubber parts in case of excessive pressure drop.
Bleed brake calipers and wheel brake cylinders after finishing test.