CDL COMBINATION PRACTICE TEST (DE)

11. Most hydraulic brake failures occur for one of two reasons, one of which is:
loss of hydraulic pressure.
excessive downshifting.
relying too much on the engine braking effect.
driving in cold weather.
12. When you inspect the coupling, make sure there is ______ between the upper and lower fifth wheel.
about 1 inch
enough space
no space
about 1/2 inch
13. When driving on slippery roads, you should NOT:
try to anticipate stops early.
watch far enough ahead to keep a steady speed.
go slowly.
use the engine brake.
14. Blocking and bracing are:
used to keep cargo from sliding and to prevent movement of cargo.
coupling devices used to connect the service air lines from the truck or tractor to the trailer.
driving techniques used to regain control when your drive wheels start to skid.
None of the above.
15. After supplying air to the trailer brake system, you should check the brake system for crossed air lines by:
checking the air brake system pressure gauge for signs of major air loss.
shutting the engine off so you can hear the brakes.
applying and releasing the trailer brakes and listening for the sound of trailer brakes.
All of the above.
16. If your vehicle thumps or vibrates heavily, it may be a sign that:
the engine belt is loose.
the brakes have failed.
one of the tires has gone flat.
you need to shift up.
17. When checking the air and electric lines to the trailer, be sure that the air lines are properly connected to the gland hands, and are:
properly greased.
secured with enough slack for turns.
secured with enough air leaks for turns.
None of the above.
18. Fully loaded rigs:
are much more likely to roll over than empty rigs.
are less likely to roll over than empty rigs.
are just as likely to roll over as empty rigs.
None of the above.
19. When you turn suddenly while pulling doubles, which trailer is most likely to turn over?
The front trailer is twice as likely to turn over as the tractor.
The rear trailer is twice as likely to turn over as the tractor.
All trailers are equally likely to turn over.
None of the above.
20. If you cannot make a right turn without entering another traffic lane, you should:
turn wide as you complete the turn.
swing wide to the left before starting the turn.
watch out for vehicles coming toward you and back up for them.
turn wide before you start the turn.
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