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
The air compressor stops pumping air at what psi?
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:
An air brake system is fully charged at what psi?
The 3 individual systems of the air brakes are the service brakes, emergency brake, and:
In ideal conditions a truck or bus with air brakes going at 55 mph would require the stopping distance of how many feet?
What negatively affects the braking power of a spring brake?
When the safety valve releases air this indicates ___________.
Generally, air governor cut-in should be at:
Spring brakes will come on automatically, but the parking brake can also be applied:
If the spring brakes are on, when should you push the brake pedal?
If you are driving down a steep downgrade and have reached your safe speed of 40 mph, you would apply the service brake until your speed dropped to ____ mph.
Besides heat, another cause of brake fade is:
In case of emergency stops, drivers should:
Compared to hydraulic brakes, air brakes add how much distance to an average 55 mph stop?
The use of brakes on a long and steep downgrade under normal conditions is only a supplement to:
You should avoid using the parking brake when _______.
If one air system is very low on pressure _______.
Which of the following helps the stop light switch work?
The braking power of the spring brakes ______.
On large buses low pressure warning devices usually signal at ______.
To avoid damaging the brakes, what should you never do while the spring brakes are applied?
What is a wig wag ?
In a dual air brake system, one system will typically control the rear brakes, and the other:
On a long or steep downgrade, how should vehicle speed be primarily controlled?