CDL Practice Test ( Updated 2024 ) Complete Questions & Answers (Solved) 100% Correct
- When uncoupling, it's a good practice to...
Answer: coupling the glad hands together and/or using the dummy couplings
- If you cross your air lines on a new trailer with spring brakes...
Answer: you won't be able to release the trailer brakes
- When traveling under 40 mph, you should follow other vehicles...
Answer: With a distance of one second for every ten feet of your vehicle length
- In order to supply air to the trailer, you must first...
Answer: Push in the tractor protection valve
- If one of the glad hands on your blue air line is missing a seal...
Answer: you might end up with a service line air leak
- . When you inspect the coupling, check to ensure that..
Answer: there's a little slack in the air lines
- The trailer hand valve should be used...
Answer: Only to test the trailer brakes
- Which one of the following statements about tractor protection valves is NOT true?
Answer: When it closes it allows air to leak from the tractor line
- You can damage the landing gear if you...
Answer: back under the trailer at an angle
- . Which one of the following is controlled by the foot brake?
Answer: The service air line
- When coupling the trailer, back up slowly until...
Answer: The fifth wheel just touches the trailer
- The earliest way to notice a trailer skid is...
Answer: By seeing it in your mirrors
- A king pin is...
Answer: pin which locks the trailer to the tractor on the fifth wheel
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- The trailer should be lowered so that...
Answer: it's raised slightly when the tractor's backed under it
- Which of the following steps comes first?
Answer: connect the air supply lines
- Before you begin coupling...
Answer: check your path for hazards
- The trailer air supply control..
Answer: Is a red, eight sided knob
- In order to inspect the coupling you should...
Answer: Use a flashlight if necessary
- You should crank the landing gear until...
Answer: It is as far up as it will go
- The fifth wheel should be checked to see if...
Answer: All of the above
- You should not back a tractor under a trailer until the whole air system is:
Answer: At normal pressure
- You are coupling a semi trailer to your tractor but have not yet backed under. The trailer
is at the right height when
Answer: It will be raised slightly when the tractor is backed under it.
- Which part of the kingpin should the locking jaws close around?
Answer: The shank
24. When you get ready to back under the semi trailer you should line up:
Answer: Directly in front of the trailer.
- How should you test the tractor semi trailer connection for security?
Answer: Pull gently forward in low gear against the locked trailer brakes, then look at it carefully
- When should you use the hand valve to park a combination vehicle?
Answer: Never
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