CDL General Knowledge TestCombination Vehicles (if applicable)Medium
A driver is inspecting the air lines (hoses) connecting the tractor and trailer. Which of the following conditions would require immediate repair before driving?
- AA small amount of condensation inside the transparent glad hand covers.
- BSlight stiffness in the hose material in cold weather.
- CMinor discoloration of the rubber due to age.
- DAir lines rubbing against each other or other parts.
Show answer & explanationAnswer & explanation
Correct answer: D. Air lines rubbing against each other or other parts.
Air lines rubbing against each other or other parts will eventually chafe through, leading to air leaks and brake failure. This is a critical safety issue requiring immediate attention.
Why the other options are wrong
- A. A small amount of condensation is normal, especially in humid or cold conditions, and does not indicate a system fault.
- B. Hose stiffness in cold weather is normal and does not immediately compromise safety unless it leads to cracking.
- C. Minor discoloration is cosmetic and not necessarily indicative of an immediate safety hazard.
Air Line Chafing
Wear and damage to air brake lines caused by friction against other components, leading to leaks.
- Causes eventual air loss.
- Requires immediate repair.
- Prevents proper brake function.
Memory trick: Rubbing lines mean trouble's signs.