# 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
Full answers + detailed explanations
Perfect for first-time, renewal applicants
DE CDL Air Brakes Test format:
25 questions
20 correct answers to pass
80% passing score
List of questions
1.
An automatic wig wag will rise out of your view when the pressure in your system rises above what psi?
2.
A driver needs to be able to see a warning when the air pressure in the service air tanks falls below ______.
3.
If you do not have automatic tank drains, how often should you drain the oil and water from the bottom of compressed air storage tanks?
4.
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.
5.
Your brakes are fading when:
6.
The supply pressure gauge shows how much pressure:
7.
The low air pressure warning signal indicates:
8.
When increased application pressure to maintain the same speed becomes necessary, you should ______.
9.
When should the spring brakes activate?
10.
When the safety valve releases air this indicates ___________.
11.
What is a \"Wig Wag\"
12.
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.
13.
When checking the air pressure buildup, pressure should build:
14.
A device that limits the amount of air provided to the front brakes is a:
15.
Pressing and releasing the brake pedal unnecessarily:
16.
If your vehicle has an alcohol evaporator, every day during cold weather you should:
17.
When inspecting the air brake system, what particular item in the engine compartment should the driver pay specific attention to?
18.
Why does a heavily loaded vehicle need a longer distance to stop?
19.
When driving an older vehicle that has a manual front brake limiting valve, drivers should:
20.
Brake linings should not be _______.
21.
If the air compressor has its own oil supply you should do what before driving?
22.
The spring brakes of a tractor will come on when the air pressure falls within _______.
23.
Vehicles without automatic air tank drains need to be checked manually to remove ________?
24.
What does ABS stand for?
25.
What is the purpose of an air storage tank?