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CDL Combination Practice Test 1 Questions
With Verified Answers.
When should you use the hand valve to park a combination vehicle? - answer✔Never
Which answer is correct for the air valves when testing the trailer service brakes only? -
answer✔Service Brake: off; Parking Brake: off; Trailer air supply: in / open; Trolley: applied
You are coupling a semi-trailer to your tractor but have not yet backed under. The trailer is at the
right height when: - answer✔The trailer will be raised slightly when the tractor is backed under it
How should you test the tractor trailer connection for security? - answer✔Pull gently forward in
low gear against the locked trailer brakes, then inspect the coupling
Which answer is correct for the air valves when testing the trailer spring / parking brakes only? -
answer✔Service Brake: off; Parking Brake: off; Trailer air supply: out; Trolley: released
Your emergency air line breaks or gets pulled apart while you are driving. The loss of pressure
will cause the: - answer✔Emergency trailer brakes to come on
You supply air to the trailer tanks by: - answer✔Pushing in the trailer air supply valve
There are two things that a driver can do to prevent a roll over. They are: (1) keep the cargo as
close to the ground as possible; and (2): - answer✔Go slowly around turns
The fifth wheel locking lever is not locked after the jaws close around the kingpin; this means: -
answer✔The coupling is not right and should be fixed before driving the coupled unit
When backing your tractor under a trailer, you should expect: - answer✔Trailer will be lifted
slightly when the tractor backs under it
Before you start to uncouple, you must - answer✔make sure the ground is solid and can support
the weight of the trailer.
During uncoupling, you should disconnect the electrical cable and - answer✔hang it with the
plug down.
CDL Combination Practice Test 1 Questions
With Verified Answers.
When should you use the hand valve to park a combination vehicle? - answer✔Never
Which answer is correct for the air valves when testing the trailer service brakes only? -
answer✔Service Brake: off; Parking Brake: off; Trailer air supply: in / open; Trolley: applied
You are coupling a semi-trailer to your tractor but have not yet backed under. The trailer is at the
right height when: - answer✔The trailer will be raised slightly when the tractor is backed under it
How should you test the tractor trailer connection for security? - answer✔Pull gently forward in
low gear against the locked trailer brakes, then inspect the coupling
Which answer is correct for the air valves when testing the trailer spring / parking brakes only? -
answer✔Service Brake: off; Parking Brake: off; Trailer air supply: out; Trolley: released
Your emergency air line breaks or gets pulled apart while you are driving. The loss of pressure
will cause the: - answer✔Emergency trailer brakes to come on
You supply air to the trailer tanks by: - answer✔Pushing in the trailer air supply valve
There are two things that a driver can do to prevent a roll over. They are: (1) keep the cargo as
close to the ground as possible; and (2): - answer✔Go slowly around turns
The fifth wheel locking lever is not locked after the jaws close around the kingpin; this means: -
answer✔The coupling is not right and should be fixed before driving the coupled unit
When backing your tractor under a trailer, you should expect: - answer✔Trailer will be lifted
slightly when the tractor backs under it
Before you start to uncouple, you must - answer✔make sure the ground is solid and can support
the weight of the trailer.
During uncoupling, you should disconnect the electrical cable and - answer✔hang it with the
plug down.
