Checking Service Brake: High and Low Pressure Tests

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.






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.
Approx. force on pedal 500 N
- After 2 minutes, pressure is permitted to drop by max. 8 %.
Testing and Bleeding Brakes






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.