View instructions
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 South Dakota CDL knowledge test. The SD 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 South Dakota CDL Manual. Take this SD CDL practice test now to prepare for the actual air brakes test!
1. In a vehicle with a dual air brake system:
each system has its own air tanks.
one system supplies air to the trailer.
both systems typically operate the regular brakes on the rear axle.
All of the above.
2. After supplying air to the trailer brake system, you should check the brake system for crossed air lines by:
shutting the engine off so you can hear the brakes.
checking the air brake system pressure gauge for signs of major air loss.
applying and releasing the trailer brakes and listening for the sound of trailer brakes.
All of the above.
3. The heavier the vehicle:
the more work the brakes must do to stop it.
the higher the center of gravity will be.
the less work the brakes must do to stop it.
None of the above.
4. With brake drums, if brakes become too hot:
your ABS will malfunction.
the air compressor will kick on to cool the brakes.
the brakes will supply too much power to the drive wheels.
the brakes may stop working.
5. The air compressor stops pumping air into the air storage tanks when air tank pressure rises to around:
125 psi.
450 psi.
100 psi.
250 psi.
6. If your ABS is not working:
it will slow your truck to a halt and force you to pull over.
the drive wheels will begin to spin, and you should take your foot off the accelerator.
you still have normal brake functions, and should drive and brake as you always have.
you should immediately bring your vehicle to a complete stop.
7. Which of the following is a reason why air tanks must be drained?
Your brakes may fail due to the water freezing.
Your battery fluid may drain out.
The governor may stop the compressor from pumping air.
Your transmission fluid may drain out.
8. A low air pressure warning signal must come on when the air pressure in the tanks falls below:
15 psi.
10 psi.
100 psi.
60 psi.
9. When a tire fails, you must:
hold the steering wheel firmly.
get out and check all the tires after you have come to a stop.
stay off the brake.
All of the above.
10. The service brake applies and releases:
the parking brake when you use the parking brake control.
the brake when you use the brake pedal during normal driving.
the brake in an emergency situation.
None of the above.
Page 1 of 3
Next page

SD CDL Air Brakes Test

Number of questions: 25
Correct answers to pass:20
Passing score:80%
Share This Online CDL Test
Rate this CDL Air Brakes Test
4.9 out of 5
based on 159 votes