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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 North Dakota CDL knowledge test. The ND 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 North Dakota CDL Manual. Take this ND CDL practice test now to prepare for the actual air brakes test!
1. Empty trucks have the best braking. True or False?
It depends on the cargo.
It depends on the truck.
2. The safety relief valve is located:
in the front brake.
on the dashboard.
on each end of the vehicle's axles.
in the first tank the air compressor pumps air to.
3. If the air compressor is belt-driven, you should check the air compressor drive belt before each trip. The belt should be:
4. To operate a vehicle equipped with air brakes, you must pass the air brakes knowledge test. Why?
If you don't pass the air brakes test, you will be restricted to driving vehicles without air brakes.
All trucks have air brakes.
If you don't pass the air brakes test, you can't get a CDL.
If you don't, you will only receive a CDL permit.
5. The low pressure warning signal will generally activate when the air pressure falls between:
80–85 psi.
85–100 psi.
55–75 psi.
30–35 psi.
6. If the air tanks are not drained:
your speed must be reduced to 5 MPH below your “safe” speed.
the water can freeze in cold weather and cause brake failure.
the air pressure in the tanks is reduced.
the spring brakes will come on.
7. _________ must have a low air pressure warning signal.
All vehicles with air brakes
Vehicles with air brakes built after 2010
Vehicles with air brakes built after 2005
Only vehicles with air brakes built before 2015
8. When is it safe to leave your vehicle unattended without applying the parking brakes or chocking the wheels?
When you are conducting your pre-trip inspection.
When the tank pressure falls to the "cut-in" pressure.
Only while you are taking a rest break.
9. Air tanks must be drained because:
if one air system is low on pressure, the rear brakes will not be operating fully.
if you don't drain the tanks yourself, your battery fluid may drain out.
when you push the brake pedal, air is let into each brake chamber.
compressed air usually has some water in it. The water can freeze in cold weather and cause brake failure.
10. With brake drums, if brakes become too hot:
your ABS will malfunction.
the brakes will supply too much power to the drive wheels.
The brakes may stop working
the air compressor will kick on to cool the brakes.
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ND CDL Air Brakes Test

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