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Free Colorado CDL Air Brakes Practice Test 2023

Do you need an 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 Colorado CDL practice test questions are based on the Colorado 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 with our free CDL Practice Test to get ready to pass the Colorado CDL Air Brake Test now. 

Our CDL practice tests:
Based on 2021 CO commercial driver's license manual
Full answers + detailed explanations
Perfect for first-time, renewal applicants
CO CDL Air Brakes Test format:
25 questions
20 correct answers to pass
80% passing score
Study now
List of questions
1.
The driver must be able to see a low air pressure warning which comes on before pressure in the service air tanks fall below ____ psi.
2.
Emergency stab braking is:
3.
The 3 individual systems of the air brakes are the service brakes, emergency brake, and:
4.
The main factor in causing brake fade is:
5.
The application pressure gauge shows how much air pressure you:
6.
To stop the vehicle, air brakes systems use _______.
7.
When you need to depress the brakes harder and harder just to maintain the same speed this means ______.
8.
Air governor cut-out should be at around:
9.
If the air compressor should develop a leak, what keeps the air in the tanks?
10.
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.
11.
The emergency spring brake release knob is:
12.
Which of these is NOT a proper time to apply the parking brakes?
13.
The trailer air supply knob is usually:
14.
To stop the vehicle, the brake shoes and linings are pushed against:
15.
To test the parking brake, stop the vehicle, put the parking brake on, and:
16.
On newer vehicles what color is the parking brake knob?
17.
At what level will the low air warning usually take effect?
18.
Brake drums should not have cracks longer than what length?
19.
Why should you check the brake adjustment often?
20.
Automatic adjusters should ________.
21.
Why should air tanks be drained completely?
22.
The belt of a belt-driven air compressor should be ________.
23.
Vehicles with air brakes _________.
24.
To check the air compressor governor's "cut in" and "cut out" pressures you need to _________.
25.
What is the function of a safety valve?
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