Combination Vehicles

32 Questions | Total Attempts: 541

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Combination Quizzes & Trivia

This will test knowledge of Combination Vehicles.


Questions and Answers
  • 1. 
    You should not back a tractor under a trailer until the whole air system is:
    • A. 

      At normal pressure

    • B. 

      Bled down to half the maximum pressure

    • C. 

      Between 60-80 psi

    • D. 

      Empty

  • 2. 
    Before you back under a trailer, make sure the:
    • A. 

      Trailer brakes are locked

    • B. 

      Tractor protection valve is normal

    • C. 

      Air brakes are off

    • D. 

      Air supply knob is in

  • 3. 
    You are coupling a semi-trailer to your tractor but have not yet backed under. The trailer is at the right height when:
    • A. 

      The kingpin is about 1 1/4" inches above the fifth wheel

    • B. 

      The end of the kingpin is even with the top of the fifth wheel

    • C. 

      It will be raised slightly when the tractor is backed under it

    • D. 

      The trailer landing gear are fully extended

  • 4. 
    You are coupling a tractor to a semi-trailer and have backed up but are not under it. What should you hook up before backing under?
    • A. 

      The electrical service cable

    • B. 

      The emergency and service air lines

    • C. 

      Nothing. Back up and lock the fifth wheel

    • D. 

      The ground cable

  • 5. 
    When you get ready to back under the semi-trailer you should line up:
    • A. 

      About 12 degrees off the line of the trailer

    • B. 

      The kingpin to engage the driver's side locking jaw first

    • C. 

      Directly in front of the trailer

    • D. 

      The left rear outer dual wheel with the kingpin

  • 6. 
    If the service air line comes apart while you are driving a combination vehicle but the emergency line stays together: what will happen right away?
    • A. 

      The emergency tractor bakes will come on

    • B. 

      The trailer's air tank will exhaust through the open line

    • C. 

      Nothing is likely to happen until you try to apply the brakes

    • D. 

      The emergency trailer brakes will come on

  • 7. 
    Which part of the kingpin should the locking jaws close around?
    • A. 

      The shank

    • B. 

      The head

    • C. 

      The base

    • D. 

      It does not matter

  • 8. 
    The fifth wheel locking lever is not locked after the jaws close around the kingpin. This means that:
    • A. 

      You can set the fifth wheel for weight balance

    • B. 

      The parking lock is off and you can drive away

    • C. 

      The coupling is not right and should be fixed before driving the coupled unit

    • D. 

      The trailer will not swivel on the fifth wheel

  • 9. 
    How should you test the tractor semi-trailer connection for security?
    • A. 

      Put the tractor in gear and pull ahead with a sharp jerk

    • B. 

      Pull gently forward in low gear against the locked trailer brakes. Then look at it carefully.

    • C. 

      Rock the trailer back and forth with the trailer brakes locked

    • D. 

      Look at it carefully

  • 10. 
    The air leaking rate for a combination vehicle (engine off, brakes on) should be less than ___ psi per minute?
    • A. 

      1

    • B. 

      2

    • C. 

      3

    • D. 

      4

  • 11. 
    When should you use the hand valve to park a combination vehicle?
    • A. 

      To park at loading docks

    • B. 

      To park on a grade

    • C. 

      Never

    • D. 

      To park for less then two hours

  • 12. 
    You have coupled with a semi-trailer. In what position should you put the front trailer supports before driving away?
    • A. 

      Raised 1/2 way with the crank handle removed

    • B. 

      Fully raised with the crank handle secured in it's bracket

    • C. 

      Three turns off the top with the crank handle secured in its bracket

    • D. 

      Raised 3/4 way with the crank handle removed

  • 13. 
    You supply air to the trailer tanks by:
    • A. 

      Pushing in the trailer air supply valve

    • B. 

      Pulling out the trailer air supply valve

    • C. 

      Connecting the service line glad hand

    • D. 

      Applying the trailer hand valve

  • 14. 
    In normal driving, some drivers use the hand valve before applying the brake pedal to prevent jackknife. Which of these statements is true.
    • A. 

      It should not be done

    • B. 

      It results in less skidding than using the brake alone

    • C. 

      It is the best way to brake and keep the truck in a straight line

    • D. 

      It lets the driver steer with both hands

  • 15. 
    The air leakage rate for a combination vehicle (engine off, brakes on) should be less than ___ psi per minute.
    • A. 

      1

    • B. 

      2

    • C. 

      3

    • D. 

      4

  • 16. 
    Why should you be sure that the fifth wheel plate is greased as required?
    • A. 

      To ensure good electrical conditions

    • B. 

      To prevent steering problems

    • C. 

      To reduce heat and noise

    • D. 

      To keep the brake system in place

  • 17. 
    A driver crosses the airlines when hooking up to an old trailer. What will happen?
    • A. 

      If the trailer has no spring brakes, you can drive away

    • B. 

      The hand valve will apply the tractor brakes instead of the trailer brakes

    • C. 

      The brake pedal will work the trailer spring brakes instead of the air brakes

    • D. 

      The brake lights will not come on when the brake pedal is pressed

  • 18. 
    After you supply air to the trailer, make sure the air lines are not crossed and the trailer brakes are working. This is done by:
    • A. 

      Turning on the parking brakes from the cab

    • B. 

      Applying and releasing the trailer brakes and listening for brake sounds

    • C. 

      Lifting the brake pedal

    • D. 

      Watching your mirrors to see if the trailer lights come on

  • 19. 
    Air lines on a combination vehicle are often colored to keep them from getting mixed up. The emergency line _____; the service line is _____.
    • A. 

      Red / Blue

    • B. 

      Black / Yellow

    • C. 

      Blue / Red

    • D. 

      Orange / Black

  • 20. 
    There are two things that a driver can do to prevent a rollover. The are; (1) Keep the cargo as close to the ground as possible; and (2):
    • A. 

      Make sure the brakes are properly adjusted

    • B. 

      Go slowly around turns

    • C. 

      Keep the fifth wheel's free play as tight as possible

    • D. 

      Keep both hands firmly on the steering wheel

  • 21. 
    Which of these statements is true?
    • A. 

      Always delay braking a heavy vehicle until you have no other choice

    • B. 

      Light vehicles need more braking power to stop than heavy ones

    • C. 

      "BOBTAIL" tractors can take longer to stop than a combination vehicle loaded to the maximum gross weight.

    • D. 

      The brake and suspension systems of comb. vehicles work best with a light load.

  • 22. 
    Semi-trailers made before 1975 that are equipped with air brakes;
    • A. 

      Are easier to brake because they are heavier

    • B. 

      Usually need a glad hand converter

    • C. 

      Ofter do not have spring brakes

    • D. 

      Can not be legally operated on interstate highways

  • 23. 
    Why should you lock the tractor glad hands ( or dummy couplers) to each other when you are not towing a trailer?
    • A. 

      The connected brake circuit becomes a back-up air tank

    • B. 

      It will keep dirt and water out of the lines

    • C. 

      If you did not, you could never build system pressure

    • D. 

      All of the above

  • 24. 
    The hand valve should be used:
    • A. 

      Only with the foot brake

    • B. 

      To test the trailer brakes

    • C. 

      Only when the trailer is fully loaded

    • D. 

      As a parking brake

  • 25. 
    The safety catch for the fifth wheel locking lever must be ___ for a coupling to be complete.
    • A. 

      Over the locking lever

    • B. 

      Under the locking lever

    • C. 

      Through the locking lever

    • D. 

      Straight up

  • 26. 
    You are coupling a tractor and semi-trailer and have connected the air lines. Before backing under the trailer, you should:
    • A. 

      Supply air to the trailer system, then pull out the air supply knob to lock the trailer brakes

    • B. 

      Make sure that the trailer brakes are off

    • C. 

      Apply the brakes twice to alert others

    • D. 

      Pull ahead to test the glad hand connections

  • 27. 
    The front trailer supports are up and the trailer is resting on the tractor. Make sure:
    • A. 

      There is enough clearance between the tops of the tractor tires and nose of trailer

    • B. 

      There is enough clearance between the tractor frame and the landing gear

    • C. 

      Both A and B are correct

    • D. 

      Neither A and B are correct

  • 28. 
    Your emergency air line breaks or gets pulled apart while you are driving. The lose of pressure will cause the:
    • A. 

      Emergency trailer brakes to come on

    • B. 

      Air compressor to unload instead of pumping air

    • C. 

      Tractor supply valve to open

    • D. 

      Tractor air to dump into the trailer tank through the service line

  • 29. 
    You have a major leak in the service line and you put on the service brakes. Service air pressure will escape and cause the:
    • A. 

      Trailer emergency brakes to come on

    • B. 

      Trailer tank pressure to be lost

    • C. 

      Tractor spring brakes to be locked on

    • D. 

      Trailer's tank pressure to go to the tractor's system

  • 30. 
    You are driving a combination vehicle when the trailer breaks away, pulling apart both air lines. You would expect the trailer brakes to come on and:
    • A. 

      The tractor to loose all air pressure

    • B. 

      The tractor protection valve to close

    • C. 

      The trailer supply valve to stay open

    • D. 

      None of the above

  • 31. 
    You are about to back a tractor under a semi-trailer. The trailer is at the right height when the:
    • A. 

      Trailer landing gear is fully extended

    • B. 

      End of the kingpin is even with the top of the fifth wheel

    • C. 

      Trailer will be lifted slightly when the tractor backs under it

    • D. 

      Kingpin is about 1 1/4 inches above the fifth wheel

  • 32. 
    How much space should be between the upper and lower fifth wheel after coupling?
    • A. 

      At least 1/2 inch

    • B. 

      None

    • C. 

      Just enough to see light through it

    • D. 

      About 1/4 inch