Home › CDL Practice Tests › Air Brakes Questions › Question 76
With the brakes fully applied and the engine off, what is the maximum allowable leakage for a combination vehicle?
- A.No more than 2 psi per minute
- B.No more than 5 psi in ten seconds
- C.Combinations are exempt from the applied test
- D.No more than 4 psi per minute after the initial pressure drop stabilizes
Correct answer
D. No more than 4 psi per minute after the initial pressure drop stabilizes
Why
Four psi per minute is the applied ceiling for combinations, reflecting their extra valves and trailer circuits. Exceeding it means the system is losing air faster than the standard allows, loaded test conditions or not.
Manual topic: Air Brakes - Air Leakage and Brake Tests · From the Air Brakes practice bank (AB-076).