Home › CDL Practice Tests › Air Brakes Questions › Question 147
What is a sign during inspection that a service brake chamber diaphragm may be leaking?
- A.The chamber pushrod returns instantly when the pedal is released
- B.Air escapes from the chamber or pressure cannot be held during an applied-brake leak test
- C.The air gauge rises to cut-out pressure normally
- D.The slack adjuster angle looks correct
Correct answer
B. Air escapes from the chamber or pressure cannot be held during an applied-brake leak test
Why
A torn or porous diaphragm lets applied pressure escape instead of pushing the rod, so that brake does less work and the system loses air. The leak test exposes the loss before the weak brake is discovered in an emergency stop.
Manual topic: Air Brakes - Brake Inspection · From the Air Brakes practice bank (AB-147).