CDL Air Brakes TestInspecting Air Brake SystemsMedium
During a pre-trip inspection, a driver notices that the air pressure gauge shows a rapid drop immediately after applying the service brakes and holding them. What does this most likely indicate?
- AA significant leak in the service brake system.
- BA properly functioning air compressor governor.
- CNormal air pressure recovery after braking.
- DAn issue with the low air warning device.
Show answer & explanationAnswer & explanation
Correct answer: A. A significant leak in the service brake system.
A rapid and significant drop in air pressure when the service brakes are applied and held indicates a substantial leak within the service brake system, which requires immediate attention.
Why the other options are wrong
- B. A properly functioning governor maintains air pressure, it doesn't cause a rapid drop.
- C. Normal air pressure recovery happens after releasing the brakes, not a rapid drop upon application.
- D. An issue with the low air warning device would not directly cause a rapid pressure drop upon brake application.
Service Brake Leak Test (Applied)
This test checks for leaks in the service brake system by applying full brake pressure and observing the air pressure gauge for drops.
- Engine off, parking brake off, wheels chocked.
- Apply full service brake pressure.
- Observe air pressure gauge for drops within 1 minute.
Memory trick: Applied brakes, rapid drop? Leak detected, don't stop!