Home › CDL Practice Tests › Air Brakes Questions › Question 9
What does the foot valve (treadle valve) do when the driver presses the brake pedal?
- A.It meters air from the reservoirs to the brake chambers in proportion to pedal pressure
- B.It starts the air compressor
- C.It drains water from all tanks at once
- D.It sets the spring brakes automatically
Correct answer
A. It meters air from the reservoirs to the brake chambers in proportion to pedal pressure
Why
The foot valve is the driver's control for service braking, delivering more air for a harder application and less for a gentle one. Releasing the pedal exhausts that air so the brakes release.
Manual topic: Air Brakes - Air Brake System Components · From the Air Brakes practice bank (AB-009).