CDL Air Brakes TestAir Brake System PartsMedium
A driver hears a continuous air leak coming from the area of the brake chambers even when the brakes are not applied. Which component is most likely malfunctioning?
- AThe air compressor governor.
- BThe safety relief valve.
- CThe brake pedal (foot) valve.
- DThe low air pressure warning system.
Show answer & explanationAnswer & explanation
Correct answer: C. The brake pedal (foot) valve.
If air is continuously leaking from the brake chambers when the brakes are not applied, it indicates that air is being sent to the chambers when it shouldn't be. The brake pedal (foot) valve controls the flow of air to the service brake chambers, so a fault in this valve is the most likely cause.
Why the other options are wrong
- A. The governor controls the compressor, not directly the flow to the brake chambers.
- B. The safety relief valve prevents over-pressurization of the tanks, not leaks at the brake chambers.
- D. The low air pressure warning system monitors pressure but does not cause air leaks.
Brake Pedal (Foot) Valve Leak
A continuous air leak from the brake chambers when the brakes are not applied often indicates a faulty brake pedal (foot) valve, which is prematurely sending air to the chambers.
- Foot valve controls air to service brake chambers.
- Internal leak can cause constant air flow.
- Leads to loss of system air pressure.
Memory trick: Leak at chambers, foot valve's to blame.