# 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
Perfect for first-time, renewal applicants
MO CDL Air Brakes Test format:
25 questions
80% passing score
List of questions
1.
A driver needs to be able to see a warning when the air pressure in the service air tanks falls below ______.
2.
When inspecting air brakes:
3.
An air compressor can be cooled by _______.
4.
All air brake equipped vehicles have:
5.
When is it OK to leave your truck unattended without applying the parking brakes and choking the wheels?
6.
In a controlled braking emergency:
7.
The spring brakes used on the chambers in a straight truck will bring you to a stop when air pressure drops below ___ psi.
8.
The main factor in causing brake fade is:
9.
The ____ shows how much pressure is in the air tanks.
10.
When performing the controlled braking method for an emergency stop, you are _________.
11.
When you release the brakes and reduce the air pressure what makes up for that air loss?
12.
In most newer vehicles, the parking brake control will be:
13.
Some vehicles are equipped with a control allowing you to apply the spring brakes gradually, called a:
14.
What happens when your brake drums get very hot?
15.
If your vehicle has an alcohol evaporator, every day during cold weather you should:
16.
In tractors and straight trucks spring brakes will come on fully when the air pressure drops to what range?
17.
In a dual air brake system, if the air pressure in one part of the system drops enough to set off the low air warning:
18.
The braking power of the spring brakes ______.
19.
Why should you drain water from compressed air tanks?
20.
Stab braking should only be used:
21.
To check the air compressor governor's "cut in" and "cut out" pressures you need to _________.
22.
Vehicles without automatic air tank drains need to be checked manually to remove ________?
23.
Manual air tank drains require:
24.
To prevent too much pressure from building up in the system, what is installed?
25.
What is the function of a safety valve?