Free Iowa CDL Air Brakes Practice Test 2022

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

Our CDL practice tests:
Based on 2022 IA commercial driver's license manual
Full answers + detailed explanations
Perfect for first-time, renewal applicants
IA 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.
To test air service brakes you should:
3.
Air brakes consist of ________.
4.
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.
5.
An air brake system is fully charged at what psi?
6.
Under normal conditions, in order to engage the parking brakes the driver should:
7.
In a controlled braking emergency:
8.
Spring brakes will generally come on at:
9.
The supply pressure gauge shows how much pressure:
10.
Where is the modulating control valve located on some vehicles?
11.
What is the purpose of an antilock braking system (ABS)?
12.
If you must make an emergency stop, you should brake so you:
13.
Spring brakes will come on automatically, but the parking brake can also be applied:
14.
The parking brake knob is usually:
15.
If your truck or bus has dual parking control valves, you can use pressure from a separate tank to:
16.
If your truck has a dual air brake system, and one of the systems is low on pressure:
17.
After the initial pressure drop, air leakage for single vehicles should be less than:
18.
Compared to hydraulic brakes, air brakes add how much distance to an average 55 mph stop?
19.
The most common problem found in roadside inspections is:
20.
The use of brakes on a long and steep downgrade under normal conditions is only a supplement to:
21.
Brake drums should not have cracks longer than what length?
22.
The braking power of the spring brakes ______.
23.
If your vehicle has an alcohol evaporator, the evaporator's purpose is to _____.
24.
Why should you drain water from compressed air tanks?
25.
On a long or steep downgrade, how should vehicle speed be primarily controlled?