The second trailer you need to couple has no spring brakes, and you have no wheel chocks. What should you do before you couple it?
Correct answer: Use the tractor to charge the trailer's air system, then unhook the emergency line.
Answer options
- ALeave the trailer free to roll so it lines up as you couple.
- BPlug its light cord into a portable generator to power its brakes.
- CUse the tractor to charge the trailer's air system, then unhook the emergency line. Correct
Why
Charging the trailer's tank fills it with air, and when you then disconnect the emergency line, that stored air sets the emergency brakes on the trailer, provided the slack adjusters are correctly adjusted. This keeps the trailer from moving while you finish the coupling; a generator would be no use, since these brakes run on air rather than electricity.
About this question
Topic: Doubles and triples License: CDL
Part of these practice sets:
Where it applies: Asked in every state.
Practice the whole set
This question is part of Coupling Doubles and Converter Dollies (28 questions). Take the full set and check your score.
Practice Coupling Doubles and Converter DolliesMore questions from Coupling Doubles and Converter Dollies
- Once the converter dolly is hooked to the rear trailer, you check the connection by eye. How much of a gap should there be where the upper fifth wheel meets the lower one?
- Your set of twins includes a loaded rear trailer that you are about to unhook. How low should its landing gear go?
- How can you release the brakes on a converter dolly?
- You have backed the converter dolly under the rear trailer of a double and are about to check the coupling. How should that trailer's landing gear be positioned?
- On a set of doubles, where should the rear trailer's landing gear be while you test the coupling?
- What are the basic components of a converter dolly?
- You release the pintle hook before the converter dolly has been pulled out from under the second trailer. What is the likely result?
- What is unique about the way triple trailers are coupled?
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