OR CDL COMBINATION PRACTICE TEST

11. Most hydraulic brake failures occur for one of two reasons, one of which is:
excessive downshifting.
loss of hydraulic pressure.
relying too much on the engine braking effect.
driving in cold weather.
12. If you discover a fire, before opening trailer doors you should:
use the fire extinguisher on the doors.
feel the doors to see if they are hot.
have a helper open the doors.
All of the above.
13. If your trailer starts to skid, you should:
release the brakes.
steer in the opposite direction.
pump the brakes.
lock the brakes.
14. The tire load rating is stated:
on each axle.
on the dashboard.
inside the suspension system.
on the side of each tire.
15. What is the minimum tread depth for tires other than front tires?
4/32 inch
8/32 inch
4/16 inch
2/32 inch
16. Emergency brakes must be must be held on by:
mechanical force.
air pressure.
water.
the locking mechanism.
17. When inspecting the coupling, make sure the fifth-wheel jaws have closed around the:
the brake camshaft.
head of the kingpin.
shank of the kingpin.
the electrical cord.
18. A bridge formula permits less maximum axle weight for axles that:
are closer together
have a high center of gravity
are further apart than normal
have poor weight balance
19. When checking air brakes on combination vehicles, which of the following is NOT part of checking that air flows to all trailers?
Using the trailer handbrake to provide air to the service line.
Pulling tractor forward until the fifth-wheel comes out from under the trailer.
Opening the emergency line shut-off valve at the rear of the last trailer.
Going to the rear of the rig.
20. If your vehicle gets stuck on the railroad tracks, you should:
get out of your vehicle and away from the tracks.
check for identifiable landmarks to give the location of the crossing.
gather up your paperwork and shipping papers while calling 911, then get out of the vehicle.
All of the above.
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