COMBINATION PRACTICE TEST - NE CDL

11. When the trailer breaks away or develops a bad leak, the tractor protection valve will close automatically and:
the trailer emergency brakes will come on.
the tractor will lose all air pressure.
the trailer supply valve will stay open.
the engine will shut down.
12. When transporting cargo, the cargo should be checked:
before the trip and after the first 150 miles.
only after the trip.
only before the trip.
before the trip and after the first 50 miles.
13. When uncoupling, after you unlock the fifth-wheel you should:
pull the tractor partially clear of the trailer.
chock the trailer wheels.
ease the pressure on the locking jaws.
pull the tractor clear of the trailer.
14. Before connecting the converter dolly to the rear trailer, make sure that:
the locking jaws rest on the kingpin.
the shut-off valves at the rear of the first trailer are open.
the trailer height is slightly lower than the center of the fifth-wheel.
the kingpin rests on the fifth-wheel.
15. Which of the following is NOT part of testing the tractor protection valve?
Stepping on and off the brake pedal several times to reduce the air pressure in the tanks.
Shutting off the engine.
Charging the trailer air brake system.
Pulling forward slowly, then applying the trailer brakes.
16. When connecting the glad hands, you should press the two seals together with the couplers at a ______ angle to each other.
45 degree
180 degree
30 degree
90 degree
17. When the ______ closes, it stops any air from going out of the tractor.
alcohol evaporator
tractor protection valve
height control valve
hand valve
18. Emergency lines on combination vehicles are often coded with the color ____ to keep from getting them mixed up with the ____ service line.
yellow; black
red; yellow
red; blue
blue; red
19. Brake fade results from, and is affected by:
brakes out of adjustment.
excessive heat caused by not relying on the engine braking effect.
excessive heat caused by using the brakes too much.
All of the above.
20. To unlock the fifth wheel, pull the release handle to the _______ position.
neutral
closed
sixth
open
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