# Free Delaware CDL Air Brakes Practice Test 2023

Do you need a Delaware Air Brakes endorsement or an L endorsement for your commercial driving license? The 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 Delaware CDL Practice test questions are based on the Delaware 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 free CDL practice test to get ready to pass the Delaware CDL Air Brake Test now.

Our CDL practice tests:
Based on 2021 DE commercial driver's license manual
Perfect for first-time, renewal applicants
DE CDL Air Brakes Test format:
25 questions
80% passing score
List of questions
1.
To test air service brakes you should:
2.
Air tanks need to be drained ______.
3.
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?
4.
The 3 individual systems of the air brakes are the service brakes, emergency brake, and:
5.
Why drain water from compressed air tanks?
6.
Normally during anti-lock braking, the driver _____.
7.
What should a driver do when the low air pressure warning signal comes on?
8.
In most newer vehicles, the parking brake control will be:
9.
"Some air brake systems have an alcohol evaporator. What may happen if you don’t keep the proper level of alcohol?"
10.
What must the air pressure be, at minimum, in both parts of a dual air brake system?
11.
Air braking takes more time than hydraulic braking because:
12.
Total stopping distance with air brakes is Perception distance + Braking Distance + Brake Lag Distance + _____.
13.
The S-cam:
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.
The trailer air supply knob is usually:
16.
To stop the vehicle, the brake shoes and linings are pushed against:
17.
Compared to hydraulic brakes, air brakes add how much distance to an average 55 mph stop?
18.
The brake pedal in an air brake system _______.
19.
How should the air leakage rate be tested?
20.
Brake drums should not have cracks longer than what length?
21.
Spring brakes are applied:
22.
What is the purpose of a supply pressure gauge?
23.
In a dual air brake system, one system will typically control the rear brakes, and the other:
24.
Vehicles with air brakes have pressure gauges connected to the _______.
25.
If your brakes are wet, what should you do to dry them quicker?