Checking the brake circuit for leaks
051 — Tester
080 - Pedal release lever
High pressure testing
1. Start the engine at moderate speed, then, by sharply releasing the gas pedal, create a deep vacuum in the intake manifold.
[Original material on the website: MercedesMAN.ru]
2. Using a special gate (080), press the foot brake pedal all the way down. The pressure loss over the next 5 minutes should not exceed 5%, - read on the tester (051).
Low pressure test
1. Turn off the engine and press the foot brake pedal several times to completely release the vacuum.
2. Using the gate (080), press the pedal so that the tester (051) registers 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).