Power Brake Assist: Testing and Inspection

Brake Booster Function Inspection

NOTE:
Make sure that air is not contained in hydraulic line before doing this check.

Air Tightness Inspection
1) Start engine.
2) Stop engine after running it for 2 minutes.
3) Depress brake pedal several times with the same load as in ordinary braking and observe pedal travel. If pedal goes down deep the first time but its travel decreases as it is depressed the second time and after, air tightness is obtained.








4) If pedal travel does not change, air tightness is not obtained.
5) If defective, inspect vacuum lines and sealing parts, and replace the faulty part. After this, repeat the entire test.








Operation Inspection
1) With engine stopped, depress brake pedal several times with the same load and make sure that pedal travel does not change.





2) Start engine while depressing brake pedal. If pedal travel increases a little, operation is satisfactory. But no change in pedal travel indicates malfunction.





Air Tightness Inspection Under Loaded Condition
1) With engine running, depress brake pedal. Then stop engine while holding brake pedal depressed.








2) Hold brake pedal depressed for 30 seconds. If pedal height does not change, condition is good. But it is not if pedal rises.