# Free Nebraska CDL Air Brakes Practice Test 2023

Our CDL practice tests:
Based on 2021 NE commercial driver's license manual
Perfect for first-time, renewal applicants
NE CDL Air Brakes Test format:
25 questions
80% passing score
List of questions
1.
The parking or emergency brake on a heavy vehicle can only be held in position by something that cannot leak away, like:
2.
An automatic wig wag will rise out of your view when the pressure in your system rises above what psi?
3.
Your truck or bus has a dual air brake system. If a low air pressure warning comes on for only one system, what should you do?
4.
A mechanical device that drops a low air warning into a drivers view is called a:
5.
If your vehicle has an alcohol evaporator, it is there to:
6.
The 3 individual systems of the air brakes are the service brakes, emergency brake, and:
7.
The spring brakes used on the chambers in a straight truck will bring you to a stop when air pressure drops below ___ psi.
8.
When you release the brakes and reduce the air pressure what makes up for that air loss?
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.
Which of these is NOT a proper time to apply the parking brakes?
12.
The emergency spring brake release knob is:
13.
All of the following apply if the low air pressure warning signal does not work except:
14.
When inspecting the air brake system, what particular item in the engine compartment should the driver pay specific attention to?
15.
How are brakes designed?
16.
Some vehicles are equipped with a separate air tank used specifically to release the spring brakes in an emergency, called a:
17.
Why should you drain water from compressed air tanks?
18.
Initial air leakage rate for combination vehicles should be:
19.
If the air compressor has its own oil supply you should do what before driving?
20.
On large buses low pressure warning devices usually signal at ______.
21.
A warning to drivers behind you that the air brakes have been applied is the:
22.
Typically, at what psi does the air compressor governor stop the compressor from pumping air?
23.
What is the purpose of an air storage tank?
24.
The warning light and buzzer will come on when the air pressure in either system drops below what psi?
25.
What is an alternative name for a brake pedal?