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

Our CDL practice tests:
Based on 2021 OK commercial driver's license manual
Full answers + detailed explanations
Perfect for first-time, renewal applicants
OK CDL Air Brakes Test format:
25 questions
20 correct answers to pass
80% passing score
List of questions
A driver needs to be able to see a warning when the air pressure in the service air tanks falls below ______.
When inspecting air brakes:
During normal driving, spring brakes are usually held back by:
A low pressure warning signal could be __________.
Modern air brakes combine three different systems. They are the service, the parking, and the _____ brakes.
The driver must be able to see a low air pressure warning which comes on before pressure in the service air tanks falls below ____ psi.
Emergency stab braking is:
The 3 individual systems of the air brakes are the service brakes, emergency brake, and:
With air brake vehicles, the parking brake should be used:
To make sure that the spring brakes come on automatically, do all of the following except:
To stop the vehicle, air brakes systems use:
When increased application pressure to maintain the same speed becomes necessary, you should ______.
In most newer vehicles, the parking brake control will be:
When using a vehicle with air brakes, the parking needs to be used _______.
Some vehicles are equipped with a control allowing you to apply the spring brakes gradually, called a:
"Some air brake systems have an alcohol evaporator. What may happen if you don’t keep the proper level of alcohol?"
If air pressure is not built up within the correct amount of time, then:
With air brake vehicles, the parking brakes should be used:
The use of brakes on a long and steep downgrade under normal conditions is only a supplement to:
Why should you drain water from compressed air tanks?
When driving an older vehicle that has a manual front brake limiting valve, drivers should:
On newer vehicles, the parking brake control knob is typically yellow, but on older vehicles, the parking brake might be what color?
Brake drums or discs _______.
If the air compressor has its own oil supply you should do what before driving?
Vehicles with air brakes _________.