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The air brakes endorsement applies to applicants who wish to drive a vehicle with air brakes in Class A, B, or C CDL. To drive a vehicle with air brakes, you must pass the air brake component of the North Carolina CDL knowledge test. The NC CDL air brakes test consists of 25 questions, and you'll need at least 20 correct answers to pass (80%). The test covers the information found in the air brakes section of the North Carolina CDL Manual. Take this NC CDL practice test now to prepare for the actual air brakes test!
1. Front-end header boards:
protect drivers from spilled cargo.
should never be used.
reduce traction.
protect drivers from cargo in case of an accident or emergency stop.
2. If you must make an emergency stop, you should:
use the hand brake before the brake pedal.
apply the brakes as hard as you can to lock them.
brake in a way that will keep your vehicle in a straight line.
None of the above.
3. You should always try to back toward the driver's side because:
you can watch the rear of your vehicle out the side window.
backing toward the left side is more dangerous.
you can more easily correct any steering errors.
None of the above.
4. Typically an air system is fully-charged at:
25 psi
125 psi
75 psi
250 psi
5. When you push the brake pedal down, air brakes work:
after about 15 seconds.
after a short delay.
only when ABS is working.
6. Antifreeze:
doesn't help the engine in any way.
helps the engine only under hot conditions.
helps the engine only when the temperature is below freezing.
helps the engine under hot conditions as well as cold conditions.
7. Hydroplaning is more likely if:
tire pressure is low.
tire tread is worn.
the road is wet.
All of the above.
8. To test the air leakage rate, with a fully-charged air system you should ____________ and time the air pressure drop.
release the parking brake, leave the engine running
check the air compressor's drive belt, chock the wheels
put alcohol into the air system, run the engine at a fast idle
turn off the engine, release the parking brake
9. The best way to know what's going on behind and to the sides of your vehicle is to:
ask your passenger(s).
lean out of the window.
use the rear view camera.
check your mirrors regularly.
10. The most common foundation brakes found on vehicles with air brakes are the:
wedge brakes.
S-cam brakes.
parking brakes.
disc brakes.
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NC CDL Air Brakes Test

Number of questions: 25
Correct answers to pass:20
Passing score:80%
Number of questions: 25
Correct answers to pass:20
Passing score:80%
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