Free Missouri CDL Air Brakes Practice Test 2022

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 2022 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
1.
The safety valve discharges automatically at the pressure of:
2.
A low pressure warning signal could be __________.
3.
To test the vehicle's service brakes, move the vehicle:
4.
The most important thing to do when a low air pressure warning comes on is:
5.
Why drain water from compressed air tanks?
6.
Excessive heat caused by using your brakes too often can also cause:
7.
The low air pressure warning signal indicates:
8.
Another name for the brake pedal is the "foot valve", or:
9.
Which braking system applies and releases the parking brakes when you use the parking brake control?
10.
When the mechanical arm of a wig wag drops into your view that means the pressure in your system has dropped below what psi?
11.
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.
12.
The manual adjustment of automatic slack adjusters is:
13.
If air pressure is not built up within the correct amount of time, then:
14.
In a dual air brake system, the first system, supplying the rear brakes, is commonly known as the "primary" system, and the other as the:
15.
Pressing and releasing the brake pedal unnecessarily:
16.
Under normal braking conditions, the vehicle:
17.
When inspecting the air brake system, what particular item in the engine compartment should the driver pay specific attention to?
18.
Controlled braking is only possible _________.
19.
Why does a heavily loaded vehicle need a longer distance to stop?
20.
The service brake system ________.
21.
At what level will the low air warning usually take effect?
22.
Pushing the brake pedal down harder __________.
23.
If air supply drops when driving, the tractor protection valve ________.
24.
What does the air compressor governor control?
25.
Vehicles with ABS have malfunction lamps that are what color?