Checking the proper functioning of the brake booster (Mercedes-Benz G-Class W463)

1. Connect the vacuum gauge (030) to the brake booster, then release the vacuum in the vacuum line by pressing the foot brake pedal several times.

2. Connect the tester (051) to the service nipple or to the brake caliper.

3. Connect the measuring device (060) to the foot brake pedal.

4. Start the engine and by sharply releasing the gas pedal create the required vacuum in the vacuum tract (0.60÷0.80 atm).

5. If the vacuum drops immediately or its depth is insufficient, you should check the condition of the sealing ring installed between the vacuum booster servo drive and the master cylinder; the possibility of failure of the control valve in the vacuum line cannot be ruled out. Assess the condition of the non-return valve, as well as the lines and vacuum receiver of the differential lock drive. On diesel models, make sure that the vacuum pump is functioning properly. Replace any failed components.

6. Press the pedal with the required force and read the tester reading. Compare the measurement results with the requirements Specifications.



7. Disconnect the gauge (060), tester (051) and vacuum gauge (030).

8. Bleed the brake system (see Section Bleeding the brake system).

Note: Only the brake circuit of the corresponding wheel requires bleeding.