CDL · Combination vehicles
Which statement about air-braked semi-trailers built before 1975 is true?
Correct answer: Many of them have no spring brakes.
Answer options
- AMany of them have no spring brakes. Correct
- BMost of them need a converter for their glad hands.
- CTheir extra weight makes them easier to stop.
Why
Trailers built before 1975 were not required to have spring brakes, so many older units depend only on air stored in the trailer's own air tank for emergency braking. If that air leaks away, nothing automatically holds the trailer in place, and it could roll.
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 are coupling to an older trailer and accidentally cross the air lines. What is the result?
- When the trailer air supply knob is pushed in, what does it do?
- On a tractor-trailer, what are glad hands used for?
- 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?
- Before the tractor backs under a semitrailer during coupling, how high should the front of the trailer be?
- When you park a tank trailer, what should hold it in place?
- Before coupling, how high should the trailer sit compared with the converter dolly's fifth wheel?
- How do you test whether the tractor and semitrailer are securely coupled?
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