CDL General Knowledge TestCombination Vehicles (if applicable)Medium
During a pre-trip inspection, a driver notices that the service (blue) glad hand on the tractor is leaking air when connected to the trailer. What is the most appropriate action?
- AApply more lubricant to the glad hand seal.
- BContinue driving, as minor leaks are common.
- CReplace the rubber seal (gasket) in the glad hand.
- DTighten the glad hand connection with a wrench.
Show answer & explanationAnswer & explanation
Correct answer: C. Replace the rubber seal (gasket) in the glad hand.
A leaking glad hand, especially from the service line, indicates a compromised seal. The most effective and appropriate action is to replace the rubber seal (gasket) inside the glad hand. This is a common maintenance item and usually resolves the leak. Tightening too much can damage the glad hand, and minor leaks are not acceptable for safe operation.
Why the other options are wrong
- A. Lubricant might temporarily mask a leak but won't fix a damaged or worn seal.
- B. Any air leak in the brake system is a safety concern and must be addressed immediately.
- D. Over-tightening can damage the glad hand or its connection, not always fixing the seal.
Glad Hand Leak Repair
Air leaks at glad hands are typically caused by worn or damaged rubber seals (gaskets) and are best repaired by replacing these seals.
- Essential for maintaining air pressure.
- Prevents brake system failure.
- Seals are inexpensive and easy to replace.
Memory trick: A leaky glad hand needs a new gasket, not just a twist.