CDL · Combination vehicles
When you park a tank trailer, what should hold it in place?
Correct answer: The spring brakes, or chocks placed under the wheels.
Answer options
- AThe spring brakes, or chocks placed under the wheels Correct
- BThe engine retarder
- CThe trailer hand valve, also called the Johnson bar
Why
Park with the spring brakes set, and if the trailer has no spring brakes, chock its wheels. Never park using the trailer hand valve: it is meant only for testing the trailer brakes, and if the air leaks away, the brakes it applied can release.
About this question
Topic: Combination vehicles License: CDL
Part of these practice sets:
Where it applies: Asked in every state.
Practice the whole set
This question is part of Trailer Air Lines and Coupling (28 questions). Take the full set and check your score.
Practice Trailer Air Lines and CouplingMore questions from Trailer Air Lines and Coupling
- You have just charged the trailer's air system. How do you verify that the lines were not crossed and that the trailer brakes respond?
- How do you test whether the tractor and semitrailer are securely coupled?
- When the trailer air supply knob is pushed in, what does it do?
- The fifth wheel jaws have closed on the kingpin, but the locking lever is not in the locked position. What does this tell you?
- Which statement about air-braked semi-trailers built before 1975 is true?
- When you look over a fifth-wheel coupling after hooking up, what should you see?
- You are coupling to an older trailer and accidentally cross the air lines. What is the result?
- For a secure coupling, the fifth wheel jaws must grip which section of the kingpin?
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