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The air brakes endorsement applies to applicants who wish to drive a vehicle with air brakes in Class A, B, or C CDL. To drive a vehicle with air brakes, you must pass the air brake component of the Iowa CDL knowledge test. The IA CDL air brakes test consists of 25 questions, and you'll need at least 20 correct answers to pass (80%). The test covers the information found in the air brakes section of the Iowa CDL Manual. Take this IA CDL practice test now to prepare for the actual air brakes test!
1. If you're feeling tired while driving you should:
drink coffee.
stop driving and get some rest.
eat something.
2. If air doesn't flow all the way to the back:
the trailer will tend to swing around.
a rollover is more likely.
your brakes will not work properly.
3. To test the service brake:
shift your transmission to a low gear, pump the brake pedal three times, then hold it down for five seconds.
gently try to pull forward with the trailer parking brake on, then release the brake.
push the brake pedal firmly while going about 5 mph.
4. Which of the following is not a braking system on a truck?
Steering brake
Parking brake
Service brake
5. Which of the following is not a type of retarder?
6. What is an important thing to remember about emergency braking?
You should never use stab braking.
Your natural response (hitting the brakes) is never the right solution.
Pushing down on the brake pedal as hard as you can will only keep the wheels locked up and cause a skid.
7. If the ABS is not working:
you still have normal brake functions.
the vehicle will have no brakes.
the vehicle will have weak brakes.
8. The maximum leakage rates per minute are ___ psi for single vehicles and ___ psi for a combination of 2 vehicles.
3; 4
3; 2
5; 6
9. To prevent drowsiness you should:
get adequate sleep before a trip.
never drive with a passenger.
schedule trips for the middle of the night.
10. If you perform the skills test in a vehicle equipped with air over hydraulic brakes:
you will be required to take the tank vehicle test.
you will be required to operate vehicles with air brakes.
you will be restricted from operating vehicles with air brakes.
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IA Air Brakes CDL Test

Number of questions: 25
Correct answers to pass:20
Passing score:80%
Number of questions: 25
Correct answers to pass:20
Passing score:80%
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