Free Illinois CDL Air Brakes Practice Test 2023

Do you need an Illinois Air Brakes endorsement or an L endorsement for your commercial driving license? The CDL Air Brake 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 Illinois 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 Illinois CDL Practice Test to get ready to pass the Illinois CDL Air Brake Test now. 

Our CDL practice tests:
Based on 2021 IL commercial driver's license manual
Full answers + detailed explanations
Perfect for first-time, renewal applicants
IL CDL Air Brakes Test format:
25 questions
20 correct answers to pass
80% passing score
List of questions
An application pressure gauge shows how much air you are applying to the brakes. Increased application pressure to maintain the same speed indicates that __________.
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.
Your truck or bus has a dual air brake system. If a low air pressure warning comes on for only one system, what should you do?
Emergency stab braking is:
With air brake vehicles, the parking brake should be used:
Normally during anti-lock braking, the driver:
What should a driver do when the low air pressure warning signal comes on?
When parking a vehicle with a modulating control valve ________.
When using a vehicle with air brakes, the parking needs to be used _______.
When your brake's main air pressure is lost ________.
If the air compressor should develop a leak, what keeps the air in the tanks?
It is not safe to drive a vehicle that has brake drums with cracks that are longer than _____ of the width of the friction area.
After the initial pressure drop, air leakage for single vehicles should be less than:
If air pressure is not built up within the correct amount of time, then:
What tells the driver how much air pressure is in the air tanks?
Under normal braking conditions, the vehicle:
In case of air pressure loss, a mechanical means of preventing the vehicle from moving is called:
To test the parking brake, stop the vehicle, put the parking brake on, and:
On newer vehicles what color is the parking brake knob?
The air compressor is connected to the engine through ______.
Some vehicles are equipped with a separate air tank used specifically to release the spring brakes in an emergency, called a:
Brake linings should not be _______.
How often should alcohol containers be checked during cold weather?
Vehicles with air brakes _________.
What is an alternative name for a brake pedal?