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📖 Combination Test
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11
When driving a set of doubles it is necessary to close which shut-off valve in the last trailer.
Front
Middle section
Back ✓ CORRECT
12
If the service line comes apart while you are driving a combination vehicle but the emergency line stays together, what will happen right away?
The trailer’s tank will exhaust through the open line.
The emergency trailer brakes will come on.
Nothing is likely to happen until you try to apply the brakes. ✓ CORRECT
13
You area about to back your tractor under a semi-trailer. The trailer is at the right height when the:
Kingpin is about 1 ¼ inches above the fifth wheel.
End of the kingpin is even with the top of the fifth wheel.
The trailer will be lifted slightly when the tractor backs under it. ✓ CORRECT
14
Your emergency air line breaks or gets pulled apart while you are driving. The loss of pressure will cause the:
Air compressor to unload of pumping air.
Emergency trailer brakes to come on. ✓ CORRECT
Trailer supply valve to open.
15
If the brakes are not released when you pushed the trailer air supply valve you should:
Check air line connection. ✓ CORRECT
Cross the airlines.
Check electrical cable.
16
Air brake equipped trailers made before 1975:
Often do not have spring brakes. ✓ CORRECT
Usually need a glad hand converter.
Cannot be legally operated on interstate highways.
17
There are two things that a driver can do to prevent a rollover. They are (1) go slow around turns and (2):
Keep both hands firmly on the steering wheel.
Keep the cargo as close to the ground as possible. ✓ CORRECT
Make sure that the brakes are properly balanced.
18
After connecting the air lines but before backing under the trailer you should:
Supply air to the trailer system, then pull out the air supply knob. ✓ CORRECT
Make sure that the trailer brakes are off.
Walk around the rig to be sure that it is clear.
19
Which part of the kingpin should the locking jaws close around?
The shank. ✓ CORRECT
The head.
The base.
20
Which part of the kingpin should the locking jaws close around?
The shank. ✓ CORRECT
The head.
The base.