Trivia Quiz: CDL Air Brake Practice Test

30 Questions

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Trivia Quiz: CDL Air Brake Practice Test


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Questions and Answers
  • 1. 
    The air brake lag distance at 55 mph on dry pavement adds about ______ feet to your stopping distance?
    • A. 

      12

    • B. 

      52

    • C. 

      32

  • 2. 
    The most important thing to do when a low air pressure warning comes on is?
    • A. 

      Upshift and drive to a safe place.

    • B. 

      Downshift and drive to a safe place.

    • C. 

      Stop and safely park as soon as possible.

  • 3. 
    • A. 

      Park on a slight incline, drain off air pressure, set the parking brakes, and check for movement.

    • B. 

      Wait for normal pressure, release the parking brake, move the truck forward slowly, and firmly step on the brake.

    • C. 

      Park on level ground, chock the wheels, engage the parking brake, and shut the engine off.

  • 4. 
    The stop light switch:
    • A. 

      Turns on the brake lights to warn drivers behind you.

    • B. 

      Tells you when you need to use your emergency brakes.

    • C. 

      Tells you when the air brake system is low on pressure.

  • 5. 
    If your vehicle has an alcohol evaporator, it is there to:
    • A. 

      Rid the wet tank of alcohol that condenses and sits at the bottom.

    • B. 

      Eliminates the need for daily tank draining.

    • C. 

      Reduce the risk of ice in air brake valves in cold weather.

  • 6. 
    The most common type of foundation brake found on heavy vehicles is the:
    • A. 

      Wedge drum.

    • B. 

      S-Cam drum.

    • C. 

      Disc brake.

  • 7. 
    During normal driving, spring brakes are usually held back by:
    • A. 

      Bolts.

    • B. 

      Spring pressure.

    • C. 

      Air pressure.

  • 8. 
    A truck with air brakes going 55 mph would require a stopping distance of?
    • A. 

      Less than 100 feet.

    • B. 

      100-300 feet.

    • C. 

      More than 300 feet.

  • 9. 
    Your truck has a properly functioning dual air brake system and minimum size air tanks. The air pressure should build from 85 to 100 psi within:
    • A. 

      30 seconds.

    • B. 

      45 seconds.

    • C. 

      60 seconds.

  • 10. 
    • A. 

      The brake drums will not be fully pressurized.

    • B. 

      Either the front or rear brakes will not be fully operational.

    • C. 

      The manual slack adjusters on the S-cam brakes are not set properly.

  • 11. 
    In air brake vehicles, the parking brakes should be used:
    • A. 

      As little as possible.

    • B. 

      To hold your speed when going downhill.

    • C. 

      Any time the vehicle is parked.

  • 12. 
    The braking power of the spring brakes:
    • A. 

      Is not affected by the condition of the service brakes.

    • B. 

      Depends on the service brake being in adjustment.

    • C. 

      Increases when the service brakes are hot.

  • 13. 
    • A. 

      Press hard on the brake pedal and apply full hand valve until you stop.

    • B. 

      Use light, steady pressure on the brake pedal.

    • C. 

      Brake hard, release the brakes when the wheels lock, and reapply the brakes when the wheels start rolling.

  • 14. 
    When you apply the brakes, the brake shoes/linings are pressed against the:
    • A. 

      Brake drum or disc.

    • B. 

      Slack adjuster.

    • C. 

      S-cam.

  • 15. 
    The air compressor governor controls:
    • A. 

      When air is pumped into the air tanks.

    • B. 

      The speed of the air compressor.

    • C. 

      Air pressure applied to the brakes.

  • 16. 
    What is emergency controlled braking?
    • A. 

      You apply the brakes as hard as you can without locking the wheels.

    • B. 

      You brake as hard as you can, release the brakes when the wheels lock, and reapply the brakes when the wheels start rolling.

    • C. 

      You apply the hand valve for one second, then push hard on the brake pedal.

  • 17. 
    The driver must be able to see a low air pressure warning which comes on before pressure in teh service air tanks fall below ______ psi?
    • A. 

      40

    • B. 

      60

    • C. 

      80

  • 18. 
    The safety valve is usually set to reduce air pressure at _____ psi.
    • A. 

      50

    • B. 

      100

    • C. 

      150

  • 19. 
    Repeatedly pressing and releasing (fanning) the brake pedal may result in:
    • A. 

      A loss of brake air pressure.

    • B. 

      A build up of brake air pressure.

    • C. 

      No change in brake air pressure.

  • 20. 
    The brake pedal in an air brake system:
    • A. 

      Controls the speed of the air compressor.

    • B. 

      Controls the air pressure applied to put on the brakes.

    • C. 

      Is connected to slack adjusters by a series of rods and linkages.

  • 21. 
    If you must make an emergency stop, brake so you:
    • A. 

      Can steer hard while braking hard.

    • B. 

      Use the hand brake first.

    • C. 

      Can steer your vehicle in a straight line.

  • 22. 
    Truck and bus parking or emergency brakes must be held on by:
    • A. 

      Air pressure.

    • B. 

      A modulating control valve.

    • C. 

      Mechanical force.

  • 23. 
    • A. 

      You have to push the brake pedal harder to control speed on a downgrade.

    • B. 

      The brake pedal feels "spongy" when you apply pressure.

    • C. 

      Your speed increases when you reduce pressure on your brake pedal.

  • 24. 
    The air compressor should stop pumping at about _____ psi.
    • A. 

      100

    • B. 

      125

    • C. 

      150

  • 25. 
    The air loss rate for a straight truck or bus with the engine off and the brake on should not be more than:
    • A. 

      1 psi in one minute.

    • B. 

      2 psi in 45 seconds.

    • C. 

      3 psi in one minute.

  • 26. 
    If your truck's air compressor has its own oil supply, when should you first check the oil level?
    • A. 

      Before driving.

    • B. 

      During your first en route inspection.

    • C. 

      Immediately after you stop driving.

  • 27. 
    The use of air brakes on downgrade is only a supplement to the:
    • A. 

      Use of spring brakes.

    • B. 

      Use of the front brake limiting valve.

    • C. 

      Braking effect of the engine.

  • 28. 
    Your vehicle has a dual air brake system. If a low air pressure warning comes on for the second system, you should:
    • A. 

      Stop the vehicle and continue only when the system is fixed.

    • B. 

      Reduce your speed, and test the remaining system while driving.

    • C. 

      Reduce your speed, and drive to the nearest garage for repairs.

  • 29. 
    All air brake equipped vehicles have:
    • A. 

      An air supply pressure gauge.

    • B. 

      An air use gauge.

    • C. 

      A backup hydraulic system.

  • 30. 
    The application pressure gauge shows how much air pressure you:
    • A. 

      Have in the air tanks.

    • B. 

      Have in the modulating control valve.

    • C. 

      Are applying to the brakes.