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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 Indiana CDL knowledge test. The IN 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 Indiana CDL Manual. Take this IN CDL practice test now to prepare for the actual air brakes test!
1. In combination vehicles with air brakes, the trailer air supply control should pop out when the air pressure falls within the range of:
100 to 120 psi
50 to 75 psi
20 to 45 psi
10 to 20 psi
2. The total stopping distance for vehicles with air brake systems is made up of __ different factors.
3. Rough acceleration:
is recommended during long trips.
can cause mechanical damage.
improves gas mileage.
is necessary to warm up the engine.
4. Antifreeze:
helps the engine under hot conditions as well as cold conditions.
doesn't help the engine in any way.
helps the engine only when the temperature is below freezing.
helps the engine only under hot conditions.
5. What is the best way to test the low air pressure warning signal?
step on and off the brake pedal while the engine is running.
pump the brakes until the air pressure drops below 45 psi.
Shut the engine off when you have enough air pressure, turn the electrical power on and step on and off the brake pedal to reduce air pressure to below 60 psi.
All of the above.
6. If your vehicle catches fire, you should pull over:
near other vehicles.
near trees.
in an open area.
at a service station.
7. Service brakes should:
only be checked by a mechanic.
be checked before each trip.
always be checked before applying the brakes.
All of the above.
8. After supplying air to the trailer brake system, you should check the brake system for crossed air lines by:
shutting the engine off so you can hear the brakes.
checking the air brake system pressure gauge for signs of major air loss.
applying and releasing the trailer brakes and listening for the sound of trailer brakes.
All of the above.
9. If the air tanks are not drained:
the air pressure in the tanks is reduced.
your speed must be reduced to 5 MPH below your “safe” speed.
the spring brakes will come on.
the water can freeze in cold weather and cause brake failure.
10. Which of the following is not a way to know when to change gears?
Use engine speed (rpm)
Check that the pressure gauge shows normal oil pressure
Use road speed (mph)
Watch your tachometer
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IN CDL Air Brakes Test

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