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 2022 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
1.
An air compressor can be cooled by _______.
2.
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.
3.
All air brake equipped vehicles have:
4.
How far should manual slack adjusters move before they need to be adjusted?
5.
A dual air brake system ________.
6.
On a long or steep downgrade, the foot brakes should be used:
7.
Why drain water from compressed air tanks?
8.
If you must make an emergency stop, you should brake so you:
9.
When the engine is off and the parking brake released, a single vehicle air loss rate should be less than ________ psi in one minute.
10.
Where is the modulating control valve located on some vehicles?
11.
When testing air leakage rates for single vehicles, initial loss rate should be less than:
12.
When parking a vehicle with a modulating control valve ________.
13.
If the spring brakes are on, when should you push the brake pedal?
14.
The level at which the air compressor stops pumping air is:
15.
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.
16.
What tells the driver how much air pressure is in the air tanks?
17.
The trailer air supply knob is usually:
18.
In case of air pressure loss, a mechanical means of preventing the vehicle from moving is called:
19.
Pushing the brake pedal down harder __________.
20.
During a normal drive, the spring brakes are held back by _____.
21.
What does the air compressor governor control?
22.
What is used to put alcohol into the system and reduce ice risk?
23.
The spring brakes of a tractor will come on when the air pressure falls within _______.
24.
To avoid damaging the brakes, what should you never do while the spring brakes are applied?
25.
What is the purpose of a supply pressure gauge?