AIR BRAKES CDL PRACTICE TEST - SOUTH CAROLINA

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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 South Carolina CDL knowledge test. The SC 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 South Carolina CDL Manual. Take this SC CDL practice test now to prepare for the actual air brakes test!
1. Front brake limiting valves were used to:
prevent overheating of the front tires.
reduce exhaust emissions.
reduce the chance of the front wheels skidding on slippery surfaces.
reduce your speed so further braking or shifting is not required.
2. If your vehicle is equipped with air brakes, loss of air pressure in the emergency line causes:
the speed of your vehicle to increase.
the trailer emergency brakes to come on.
the trailer spring brakes to come on.
All of the above.
3. Combination vehicles have __ air lines.
4
3
2
1
4. Excessive use of the service brakes results in overheating and leads to:
reduction of the brake drums.
brake fade.
low air pressure.
poor traction.
5. When the low air pressure warning light and buzzer first come on, you should:
downshift and slow down.
speed up to restore pressure.
bring the vehicle to a safe stop right away.
immediately put alcohol into the air system.
6. The application pressure gauge:
protects the tank and the rest of the system from too much pressure.
shows how much air pressure is being applied to the brakes.
tells you how much pressure is in the air tanks.
stops the compressor from pumping air.
7. Supply pressure gauges tell you:
when the pressure in the system drops below 60 psi.
how much pressure is in the air tanks.
when the air pressure in the tanks falls below 60 psi.
how much air pressure you are applying to the brakes.
8. Hydroplaning is more likely if:
tire tread is worn.
the road is wet.
tire pressure is low.
All of the above.
9. Before starting down a hill, you should:
release the accelerator and shift to Neutral at the same time.
look for an escape route.
apply the brakes hard.
slow down and shift to a lower gear.
10. Vehicles with ABS have ______ ABS malfunction lamps on the instrument panel.
yellow
blue
green
orange
 
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SC Air Brakes Test

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