Free Missouri CDL Air Brakes Practice Test 2023

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

Our CDL practice tests:
Based on 2021 MO commercial driver's license manual
Full answers + detailed explanations
Perfect for first-time, renewal applicants
MO 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?
The air loss rate for a straight truck or bus with the engine off and the brakes on should not be more than:
"A slack adjuster’s free play needs to be adjusted if it is more than about ______ when you pull hard on it."
At 55 mph on dry pavement, the air brake lag distance is how many feet?
An air brake system is fully charged at what psi?
If your truck has a properly functioning dual air brake system and minimum size air tanks, the air pressure should build up from 85 to 100 psi within how many seconds?
If your vehicle has an alcohol evaporator, it is there to:
What is the purpose of an antilock braking system (ABS)?
When does the air compressor governor allow air to start pumping?
If the low air warning comes on while you are driving, you should:
If the air compressor should develop a leak, what keeps the air in the tanks?
The safety valve reduces pressure at ___ psi.
If your truck or bus has dual parking control valves, you can use pressure from a separate tank to:
When brakes are applied, the brake shoes will press against the:
The level at which the air compressor stops pumping air is:
Which of these is NOT a proper time to apply the parking brakes?
Average stopping distance under normal conditions at 55 mph is:
To stop the vehicle, the brake shoes and linings are pushed against:
To test the parking brake, stop the vehicle, put the parking brake on, and:
Brake drums should not have cracks longer than what length?
How are brakes designed?
On large buses low pressure warning devices usually signal at ______.
What is used to put alcohol into the system and reduce ice risk?
To avoid damaging the brakes, what should you never do while the spring brakes are applied?
What is the purpose of a supply pressure gauge?