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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. Do NOT use the parking brakes:
when you leave your vehicle.
if the brakes are very hot.
to test that they work.
when you park for less than two hours.
2. You hear a loud "bang" which sounds like a tire blowout. You should:
inspect your tires with your mirrors.
check the tires at the next stop.
keep driving as normal.
assume you have a tire failure.
3. If the air pressure gets too low:
the brakes will not work.
ABS will help maintain vehicle control.
you should set the parking brake.
the brakes will lock up.
4. Empty trucks have the best braking. True or False?
It depends on the truck.
It depends on the cargo.
True.
False.
5. If the air compressor is belt-driven, you should check the air compressor drive belt before each trip. The belt should be:
cracked.
loose.
tight.
worn.
6. The alcohol evaporator:
ensures the coolant temperature gauge remains in the normal range.
shows how much air pressure you are applying to the brakes.
eliminates the need for daily air tank drainage.
helps to reduce the risk of ice in air brake valves and other parts in cold weather.
7. If you're feeling tired while driving you should:
drink coffee.
eat something.
increase your speed to get to your destination quicker.
stop driving and get some rest.
8. The air tanks should be drained completely to remove:
carbon monoxide.
water and oil.
air.
the radiator cap.
9. 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:
3 psi for single vehicles and 4 psi for a combination of 2 vehicles.
5 psi for single vehicles and 6 psi for a combination of 2 vehicles.
2 psi for single vehicles and 5 psi for a combination of 2 vehicles.
1 psi for single vehicles and 3 psi for a combination of 2 vehicles.
10. If a vehicle is equipped with ABS, when you start the engine:
the spring brakes will come on.
the wheels will lock up.
the trailer emergency brakes will come on.
the ABS indicator light on the dash should come on and then turn off.
 
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Frequently Asked Questions

Here are the age requirements of the graduated driver's license program to obtain a class D driver's license in South Carolina:
  • For a beginner's permit, you must be at least 15 years old.
  • For a conditional driver’s license, you must be at least 15 but less than 16 years old and have held your permit for at least 180 days.
  • For a special restricted driver’s license, you need to be at least 16 but less than 17 years old. Additionally, you must have held your beginner’s permit for at least 180 days or have a conditional license.
  • For a regular driver’s license, you must have held a conditional or special restricted license for at least one year, or you must be at least 17 years old and have held a beginner’s permit for 180 days.

To take the DMV written test in South Carolina, you can visit a South Carolina DMV branch without appointment. It's important to note that permit tests are typically offered at specific hours, so contact the office you've chosen to find out when you have to go.
Make sure you've got all you need when you go to the DMV office. You must bring:
  • Proof of South Carolina residency (such as school or employment records, utility bills, bank statements, etc.). For a REAL ID permit, you'll need to present two proofs of residency.
  • Proof of U.S. citizenship/identity, name, and date of birth.
  • Proof of Social Security Number.
If you're under 18 years old, a parent or legal guardian must sign the Consent for Minor at the DMV office, unless you are an emancipated minor or married.

To prepare for the DMV written test, read the South Carolina Driver's Handbook. Pay attention to road signs, parallel parking, turning, passing a vehicle, yielding the right of way, etc. Test your knowledge with our practice tests or sign up for Premium, which offers extra resources to get ready for your exam.

New drivers in South Carolina face specific restrictions. If you have a beginner's permit, you can drive:
  • From 6 a.m. to midnight with a licensed driver who is at least 21 years old with one year or more of driving experience, seated near you.
  • From midnight to 6 a.m., with any driver listed on your Consent for Minor form, seated beside you.

If you have a conditional or special restricted license:
  • You can transport a maximum of two passengers under 21, unless accompanied by a licensed adult who is at least 21 (except for siblings).
  • You can drive alone from 6 a.m. to 6 p.m. (8 p.m. during daylight savings time).
  • You can drive between 6 p.m. (8 p.m. during daylight savings time) and midnight if accompanied by a licensed driver who is at least 21.
  • You can drive from midnight to 6 a.m. with a parent/guardian.

A beginner's permit remains valid for a period of twelve months. You have the option to renew it for another year if you're eligible. The renewal process can be completed online and you are required to pay a fee. However, if the permit has been expired for more than nine months, you'll need to retake the DMV test.

SC CDL Air Brakes Test

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