Home › CDL Practice Tests › Air Brakes Questions › Question 16
What does a quick-release valve do in an air brake system?
- A.It builds tank pressure above the governor setting
- B.It exhausts air from the brake chambers quickly so the brakes release faster
- C.It locks the parking brakes permanently
- D.It measures tread depth at the wheel
Correct answer
B. It exhausts air from the brake chambers quickly so the brakes release faster
Why
When the driver lifts off the pedal, a quick-release valve dumps chamber air nearby instead of sending it all the way back to the foot valve. Faster exhaust means faster release and less brake drag.
Manual topic: Air Brakes - Air Brake System Components · From the Air Brakes practice bank (AB-016).