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What danger does a gap between the trailer apron (upper coupler plate) and the fifth wheel plate indicate?
- A.A gap is normal and adds flexibility
- B.The fifth wheel needs less grease
- C.The kingpin may be hooked on top of the jaws or the trailer is high-hooked, and the connection can fail
- D.The trailer is loaded too lightly
Correct answer
C. The kingpin may be hooked on top of the jaws or the trailer is high-hooked, and the connection can fail
Why
Apron and plate should sit flush once coupled, with the weight resting on the fifth wheel. A visible gap means the pin is not seated in the jaws correctly, and the trailer can tear loose under the first hard pull or turn.
Manual topic: Combination Vehicles - Coupling · From the General Knowledge practice bank (GK-134).