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
If you do not have automatic tank drains, how often should you drain the oil and water from the bottom of compressed air storage tanks?
Modern air brakes combine three different systems. They are the service, the parking, and the _____ brakes.
The driver must be able to see a low air pressure warning which comes on before pressure in the service air tanks falls below ____ psi.
The most important thing to do when a low air pressure warning comes on is:
If you must make an emergency stop, you should brake so you:
The application pressure gauge shows how much air pressure you:
To stop the vehicle, air brakes systems use:
The safety valve is set automatically when pressure is:
The level at which the air compressor stops pumping air is:
When checking the air pressure buildup, pressure should build:
The parking brake should not be used when wet in freezing temperatures, or:
Total stopping distance with air brakes is Perception distance + Braking Distance + Brake Lag Distance +:
After the initial pressure drop, air leakage for combination vehicles should be less than:
A device that limits the amount of air provided to the front brakes is a:
The S-cam:
The most common type of foundation brake is?
Why should you check the brake adjustment often?
At minimum, a dual air system should build up to what psi in the primary and secondary systems?
In tractors and straight trucks spring brakes will come on fully when the air pressure drops to what range?
Why do air brakes take longer to stop than hydraulic brakes?
Stab braking should only be used:
If the air compressor has its own oil supply you should do what before driving?
The safety valve in the air compressor tank is set to open at _____.
To prevent too much pressure from building up in the system, what is installed?
The warning light and buzzer will come on when the air pressure in either system drops below what psi?