Home › CDL Practice Tests › Air Brakes Questions › Question 228
A dryer that never purges, or tanks that keep filling with water despite a dryer, most likely indicates what?
- A.Proof that the compressor is oversized for the vehicle
- B.A reason to stop draining tanks altogether
- C.Normal operation in humid weather only
- D.A dryer, purge valve, cartridge, or related fault that needs service before moisture reaches the brake valves
Correct answer
D. A dryer, purge valve, cartridge, or related fault that needs service before moisture reaches the brake valves
Why
The dryer is the main line of defence against water in modern systems, and its failure shows up downstream as wet tanks and sticking valves. Servicing the cartridge or purge mechanism restores that protection.
Manual topic: Air Brakes - Air Dryers · From the Air Brakes practice bank (AB-228).