Checking Function of Brake Booster With Master Cylinder

- Unscrew bleeder screw on caliper. Connect and bleed a pressure tester.





- Mount a pedal force meter on brake pedal. Apply a force of 200 N (45 lb) on brake pedal with the engine running (full hydraulic reservoir). In so doing the hydraulic line pressure of the service brakes must reach the specified value 70-90 bar (994-1278 lb sq in). The brake booster must be replaced, if the values are not reached with the service brakes in perfect operating condition.

NOTE: This test does not include the service brake leak test.