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During the applied-pressure leakage test on a combination vehicle, roughly how much pressure loss in one minute is the most that is considered acceptable?
- A.About 15 psi
- B.About 25 psi
- C.About 4 psi with the brake pedal held down
- D.Any amount, as long as the pedal feels firm
Correct answer
C. About 4 psi with the brake pedal held down
Why
The commonly taught limits are about 3 psi per minute for a single vehicle and 4 psi per minute for a combination vehicle with the brakes applied. More loss than that means a leak serious enough to take the vehicle out of service until repaired.
Manual topic: Air Brakes - Air Leakage Check · From the General Knowledge practice bank (GK-126).