Checking Service Brake: High and Low Pressure Tests

Caution: The high and low-pressure tests (leak check) must be conducted with the engine switched off.





High-Pressure Leak Test:
Perform test on both brake circuits.
1st brake circuit, front axle
2nd brake circuit, rear axle
Unscrew bleeder screw, connect pressure tester and bleed.





Depress brake pedal with specified force, refer to Brakes, Specification and hold depressed with a pedal prop. 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 - 5 bar.
Vehicle and tester must remain still as motion would cause incorrect test results.
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.