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.
A driver needs to be able to see a warning when the air pressure in the service air tanks falls below ______.
2.
All air brake equipped vehicles have:
3.
Excessive use of the service brakes results in overheating which can lead to:
4.
At 55 mph on dry pavement, the air brake lag distance is how many feet?
5.
A mechanical device that drops a low air warning into a drivers view is called a:
6.
Why drain water from compressed air tanks?
7.
While applying the brakes, what tells the driver how much air pressure is being used?
8.
If you must make an emergency stop, you should brake so you:
9.
To stop the vehicle, air brakes systems use:
10.
When the air system is low ________.
11.
Generally, air governor cut-in should be at:
12.
When checking the low pressure warning signal, it should turn on before the pressure drops below what psi?
13.
To check the free play of manual slack adjusters of S-cam brakes, you should park on:
14.
The safety valve is set automatically when pressure is:
15.
Why is manually adjusting automatic slack adjusters dangerous?
16.
When checking the air pressure buildup, pressure should build:
17.
The emergency spring brake release knob is:
18.
If air pressure is not built up within the correct amount of time, then:
19.
To stop the vehicle, the brake shoes and linings are pushed against:
20.
All of the following apply if the low air pressure warning signal does not work except:
21.
On newer vehicles what color is the parking brake knob?
22.
If one air system is very low on pressure _______.
23.
Why do air brakes take longer to stop than hydraulic brakes?
24.
During a normal drive, the spring brakes are held back by _____.
25.
Water and oil _______.