CDL Air Brakes TestAir Brake System PartsHard
A driver hears a continuous air leak coming from the area of the brake chambers, even when the service brakes are not applied. The air pressure is steadily dropping. Which component is most likely at fault?
- AAn air storage tank safety valve.
- BThe brake pedal (foot) valve.
- CThe anti-lock braking system (ABS) module.
- DThe air compressor governor.
Show answer & explanationAnswer & explanation
Correct answer: B. The brake pedal (foot) valve.
If there's a continuous air leak at the brake chambers when the brakes are not applied, it means air is constantly being sent to them. The brake pedal (foot) valve is responsible for controlling the flow of air to the service brake chambers. A leak in this valve, or if it's stuck partially open, would cause air to leak past it and out through the chambers.
Why the other options are wrong
- A. A safety valve releases excess pressure from the air tanks, not typically from the brake chambers.
- C. An ABS module primarily modulates brake pressure during a skid, it doesn't typically cause a constant air leak from the chambers when brakes are off.
- D. The governor controls compressor cut-in/cut-out, not direct air flow to brake chambers.
Brake Pedal (Foot) Valve Leak
A malfunction in the foot-operated valve that controls air to the service brake chambers, leading to unintended air flow or leakage.
- Can cause continuous air leak at brake chambers.
- Leads to rapid air pressure drop.
- Affects service brake operation.
Memory trick: Foot Valve Failing, Air is Ailing.