CDL Combination Vehicles TestInspecting Combination VehiclesHard
During a pre-trip inspection of a combination vehicle, you find that the service line (blue glad hand) on the trailer is severely chafed and worn, exposing the inner reinforcement layers. The emergency line (red glad hand) appears to be in good condition. What is your immediate action?
- AReplace the damaged service line immediately before operating the vehicle.
- BSwap the service line with the emergency line since it's in better condition.
- CReduce air pressure in the service line to prevent further damage.
- DApply electrical tape around the chafed area and continue with the trip.
Show answer & explanationAnswer & explanation
Correct answer: A. Replace the damaged service line immediately before operating the vehicle.
A severely chafed air line, especially exposing inner layers, is a critical defect. It could lead to a sudden loss of air pressure to the service brakes, causing a dangerous situation. The line must be replaced immediately for safety.
Why the other options are wrong
- B. Swapping lines is incorrect; they serve different purposes and are color-coded for safety. Also, the emergency line could then become chafed.
- C. Reducing air pressure compromises braking capability and does not fix the physical damage to the line.
- D. Tape is a temporary fix and inadequate for high-pressure air lines; it will not prevent failure.
Air Line Integrity
Air lines transmit compressed air for braking. Their integrity is paramount; any significant damage can lead to partial or complete brake failure.
- Service (blue) and emergency (red) lines.
- Must be free of cuts, chafing, and leaks.
- Coiled lines should not sag or rub.
- Damage can cause sudden air loss.
Memory trick: A chafed line is a ticking time bomb for your brakes.