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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 Massachusetts CDL knowledge test. The MA 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 Massachusetts CDL Manual. Take this MA CDL practice test now to prepare for the actual air brakes test!
1. The air compressor stops pumping air into the air storage tanks when air tank pressure rises to around:
125 psi.
450 psi.
100 psi.
250 psi.
2. In combination vehicles with air brakes, the trailer air supply control should pop out when the air pressure falls within the range of:
10 to 20 psi
50 to 75 psi
100 to 120 psi
20 to 45 psi
3. A broken exhaust system:
does not cause problems.
can improve fuel efficiency.
poses no threat to the driver.
can let poisonous carbon monoxide to leak into the cab.
4. To perform an applied leakage test, the vehicle’s air pressure should be built up to maximum pressure. Check the air gauge to see that the air pressure should drop no more than:
2 psi for single vehicles and 5 psi for a combination of 2 vehicles.
5 psi for single vehicles and 6 psi for a combination of 2 vehicles.
3 psi for single vehicles and 4 psi for a combination of 2 vehicles.
1 psi for single vehicles and 3 psi for a combination of 2 vehicles.
5. Air storage tanks:
hold compressed air for the brakes.
use parts of the service brake systems to stop the vehicle in a brake system failure.
pump air into the air storage tanks.
are installed in the first tank the air compressor pumps air to.
6. Too little weight on the driving axles can cause:
poor traction.
mechanical damage.
longer stopping distances.
poor visibility.
7. The application pressure gauge:
shows how much air pressure is being applied to the brakes.
tells you how much pressure is in the air tanks.
protects the tank and the rest of the system from too much pressure.
stops the compressor from pumping air.
8. While driving, you should use your mirrors to:
check where the rear of your vehicle is while you make turns.
check the condition of the tires and cargo.
know where other vehicles are around you.
All of the above.
9. If stopped on a hill, how can you start moving without rolling back?
Partly engage the clutch before you take your right foot off the brake, put on the parking brake if necessary.
Release the parking brake before you have applied enough engine power to keep from rolling back.
Press on the gas pedal, even if you have to roll back a little.
None of the above.
10. When should you be particularly careful about high winds?
When emerging from a tunnel
When driving in winter
When going downhill
When driving at night
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MA CDL Air Brakes Test

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