CDL General Knowledge TestCombination Vehicles (if applicable)Hard
A driver is inspecting the air lines (hoses) connecting the tractor to the trailer. Which of the following conditions represents a critical safety defect that would put the vehicle out of service?
- AAir lines touching the frame or other components.
- BSlight discoloration from age.
- CSmall cracks on the glad hand rubber seals.
- DMinor scuff marks on the outer jacket.
Show answer & explanationAnswer & explanation
Correct answer: A. Air lines touching the frame or other components.
Air lines touching the frame or other components can lead to chafing, which can wear through the hose and cause an air leak. Air leaks in the brake system are critical safety defects that can lead to brake failure and put the vehicle out of service.
Why the other options are wrong
- B. Discoloration alone is not a safety defect.
- C. Small cracks on glad hand seals are a defect, but chafing leading to potential hose failure is generally considered more severe due to the risk of sudden, complete air loss.
- D. Minor scuffs are typically cosmetic and not immediately critical.
Air Line Chafing
Chafing occurs when air lines rub against other vehicle components, causing wear that can lead to air leaks and brake system failure.
- Can cause sudden air loss.
- A critical out-of-service defect.
- Lines must be properly secured and routed.
Memory trick: Rubbing pipes mean trouble, a leak will make your air bubble.