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 Carolina CDL knowledge test. The SC 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 Carolina CDL Manual. Take this SC CDL practice test now to prepare for the actual air brakes test!
1. You should always try to back toward the driver's side because:
backing toward the left side is more dangerous.
you can watch the rear of your vehicle out the side window.
you can more easily correct any steering errors.
None of the above.
2. When driving in a construction zone, if a construction worker is near the road, you should:
further reduce your speed.
come to a complete stop.
maintain a constant speed.
speed up.
3. A low air pressure warning signal:
is required on all vehicles without air brakes.
is optional on vehicles with air brakes.
is required on vehicles with air brakes.
None of the above.
4. You are driving on a steep downgrade. If your safe speed is 35 mph, you should apply the brakes when your speed reaches:
35 mph
25 mph
30 mph
45 mph
5. You should drain your air tanks:
every month.
at least once a week.
at the beginning of each trip.
at the end of each working day.
6. Rough acceleration:
can cause mechanical damage.
improves gas mileage.
is recommended during long trips.
is necessary to warm up the engine.
7. In a vehicle with a dual air brake system:
one system supplies air to the trailer.
both systems typically operate the regular brakes on the rear axle.
each system has its own air tanks.
All of the above.
8. You should NOT use the parking brakes if:
the brakes are very hot.
the brakes are too dry.
the brakes are cold.
All of the above.
9. If you must make an emergency stop, you should:
apply the brakes as hard as you can to lock them.
use the hand brake before the brake pedal.
brake in a way that will keep your vehicle in a straight line.
None of the above.
10. In combination vehicles with air brakes, the trailer air supply control should pop out when the air pressure falls within the range of:
20 to 45 psi
100 to 120 psi
50 to 75 psi
10 to 20 psi
Page 1 of 3
Next page

SC Air Brakes CDL Test

Number of questions: 25
Correct answers to pass:20
Passing score:80%
Share This Online CDL Test
Rate this Air Brakes CDL Test
4.6 out of 5
based on 376 votes