CDL · Combination vehicles
When you drive a tractor with no trailer attached, why should its glad hands be locked together or onto dummy couplers?
Correct answer: To keep dirt and water from getting into the air lines.
Answer options
- ATo let the air system build up to full pressure
- BTo turn the brake lines into an extra reserve air tank
- CTo keep dirt and water from getting into the air lines Correct
Why
Coupling the glad hands to each other or to dummy couplers seals their openings, so road grime, moisture and debris cannot get into the air lines and cause brake trouble.
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
- During coupling, your tractor is in front of the semitrailer but not yet under it. What do you connect before backing under?
- Before coupling, how high should the trailer sit compared with the converter dolly's fifth wheel?
- What must you confirm right before backing the tractor under a trailer?
- Before the tractor backs under a semitrailer during coupling, how high should the front of the trailer be?
- Which sequence is correct for testing the trailer service brakes?
- On a tractor-trailer, what are glad hands used for?
- As air pressure drops, a tractor protection valve shuts by itself at a level set by its manufacturer. That level usually falls within which range?
- You are coupling to an older trailer and accidentally cross the air lines. What is the result?
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