Free North Carolina CDL Air Brakes Practice Test 2023

Do you need an Air Brakes endorsement or an L endorsement for your commercial driving license? The North Carolina CDL Air Brake test has some differences from other endorsements because your license will receive a mark of restriction if you fail the test. So having good preparation before exam day is very necessary. To ensure that our questions are relevant, all of our CDL practice test packs are based on the NC CDL Manual. Each question has a detailed explanation for you to thoroughly learn the format and the topic. Don't be afraid of having a restriction on your license. Let’s try our NC CDL Test to get ready to pass the North Carolina CDL Air Brake Test now. 

Our CDL practice tests:
Based on 2021 NC commercial driver's license manual
Full answers + detailed explanations
Perfect for first-time, renewal applicants
NC CDL Air Brakes Test format:
25 questions
20 correct answers to pass
80% passing score
List of questions
An air compressor can be cooled by _______.
The air loss rate for a straight truck or bus with the engine off and the brakes on should not be more than:
Air tanks need to be drained ______.
The proper use of the brakes when going down a long steep grade after selecting a proper gear is to brake until your speed is about ____ below the posted speed and release your brake.
An air brake system is fully charged at what psi?
The supply pressure gauge shows how much pressure:
Brake fade is caused by:
When you need to apply more pressure to help your brakes work normally effectively, this means that your brakes are fading. Which of the following can cause fading brakes?
Another name for the brake pedal is the "foot valve", or:
When parking a vehicle with a modulating control valve ________.
What is the purpose of an antilock braking system (ABS)?
Spring brakes will come on automatically, but the parking brake can also be applied:
If your truck has a dual air brake system, and one of the systems is low on pressure:
The emergency spring brake release knob is:
The parking brake should not be used when wet in freezing temperatures, or:
In case of emergency stops, drivers should:
A device that limits the amount of air provided to the front brakes is a:
The trailer air supply knob is usually:
If you need to make an emergency stop, you should brake so that you can ________.
You should avoid using the parking brake when _______.
Why does a heavily loaded vehicle need a longer distance to stop?
Brake drums should not have cracks longer than what length?
During a normal drive, the spring brakes are held back by _____.
To check the air compressor governor's "cut in" and "cut out" pressures you need to _________.
What brake system uses part of the service and parking brake systems to stop the vehicle in the event of a brake system failure?