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.
The stop light switch:
2.
Air tanks need to be drained ______.
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.
If your vehicle has an alcohol evaporator, it is there to:
5.
Your brakes are fading when:
6.
The low air pressure warning signal indicates:
7.
What negatively affects the braking power of a spring brake?
8.
Which braking system applies and releases the parking brakes when you use the parking brake control?
9.
In most newer vehicles, the parking brake control will be:
10.
When you need to depress the brakes harder and harder just to maintain the same speed this means ______.
11.
When using a vehicle with air brakes, the parking needs to be used _______.
12.
If the low air warning comes on while you are driving, you should:
13.
"Some air brake systems have an alcohol evaporator. What may happen if you don’t keep the proper level of alcohol?"
14.
What is a \"Wig Wag\"
15.
The manual adjustment of automatic slack adjusters is:
16.
Average stopping distance under normal conditions at 55 mph is:
17.
After the initial pressure drop, air leakage for combination vehicles should be less than:
18.
With air brake vehicles, the parking brakes should be used:
19.
You should avoid using the parking brake when _______.
20.
The most common type of foundation brake is?
21.
In tractors and straight trucks spring brakes will come on fully when the air pressure drops to what range?
22.
The air tanks must be drained because:
23.
Brake linings should not be _______.
24.
The parking brake should be used:
25.
What happens when pressure is put on the air brakes?