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What is one sign during coupling that air is leaking badly at the trailer connection?
- A.The engine idles more quietly
- B.The trailer lights flicker once
- C.A loud hissing at the gladhands and trailer pressure that will not build normally
- D.The landing gear turns easily
Correct answer
C. A loud hissing at the gladhands and trailer pressure that will not build normally
Why
Air escaping at the coupling is air the trailer brakes never receive. Hissing plus slow pressure build-up points to a bad seal, a cracked gladhand, or a line not fully seated.
Manual topic: Combination Vehicles - Coupling · From the Combination Vehicles practice bank (CV-034).