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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 Ohio CDL knowledge test. The OH 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 Ohio CDL Manual. Take this OH CDL practice test now to prepare for the actual air brakes test!
1. To operate a vehicle equipped with air brakes, you must pass the air brakes knowledge test. Why?
All trucks have air brakes.
If you don't pass the air brakes test, you will be restricted to driving vehicles without air brakes.
If you don't pass the air brakes test, you can't get a CDL.
2. Antifreeze:
helps the engine only when the temperature is below freezing.
helps the engine under hot conditions as well as cold conditions.
helps the engine only under hot conditions.
3. When going down a steep downgrade, you should:
use the parking brake.
use a low gear, and a proper braking technique.
avoid braking and rely on engine braking.
4. How should you apply the brakes when going down a steep downgrade?
Apply the brakes whenever you reach your safe speed, until your speed has been reduced to 5 mph below your safe speed.
Apply the brakes as hard as you can without locking the wheels.
Apply the brakes when you reach the bottom of the downgrade.
5. A broken exhaust system:
can improve fuel efficiency.
can let poisonous carbon monoxide to leak into the cab.
poses no threat to the driver.
6. Air tanks must be drained completely to:
remove all moisture and oil.
pump water and compressor oil into the tanks.
remove all the air.
7. What factors can cause brakes to fade?
Slippery surfaces and shaded areas.
Dirt roads and in unpaved yards.
Excessive heat and brakes out of adjustment.
8. It may not be safe to operate at legal maximum weights:
during bad weather or in mountains.
in hot weather.
on two-way streets.
9. To prevent rollover, you should:
go slowly around turns.
keep the cargo as close to the ground as possible.
All of the above.
10. Service brakes should:
be checked before each trip.
only be checked by a mechanic.
always be checked before applying the brakes.
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OH Air Brakes CDL Test

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