Checking the brake circuit for leaks
051 - Tester
080 - Gate for squeezing the pedal
High pressure test
1. Start the engine at moderate speed, then, by sharply releasing the gas pedal, create a deep vacuum in the intake manifold.
2. With a special gate (080) fully depress the foot brake pedal. Pressure loss over the next 5 minutes should be no more than 5% - read on the tester (051).
Low pressure test
1. Shut off the engine and depress the foot brake pedal completely to release the vacuum.
2. Using the gate (080) depress the pedal until the tester (051) registered a pressure of about 3 bar, - the pressure must be maintained for at least 2 minutes.
3. Finally, bleed the brake system (see Section Bleeding the brake system).