Air Brakes #1
Air Brakes Endorsement Test | South Carolina 2025 #1 Page 4 of 4
Train for FREE online with our South Carolina CDL air brake test. The official exam test consists of several obligatory parts, with all of them checking your knowledge of different blocks of road rules. If you need to obtain a SC Class A/Class B driver license in 2025, practice as much as possible. Free sample tests published on our website will help you check and improve your knowledge and boost your grades. Please bear in mind that the requirements for CDL may vary from state to state.
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19 . Front brake limiting valves were intended to:
Remove uncertainty when applying the brakes.
Some older vehicles with air brakes have front brake limiting valves. These valves were intended to reduce the risk of front wheels skidding. However, research has shown that such devices are unnecessary, so they should be left in the "normal" position.
20 . The most common type of foundation brake used is the:
P-cam disc brake.
The most common type of foundation brake is an s-cam drum brake.
21 . What does ABS do?
Prevent the brakes from being used if downshifting would be more effective
The purpose of an Anti-Lock Braking System (ABS) is to prevent wheels from locking up during hard applications of the brakes, especially on slippery surfaces.
22 . An alcohol evaporator in an air brake system:
Some air brake systems include an evaporator that introduces alcohol into the system. The alcohol can help prevent ice from forming within the system.
23 . What can happen if the air pressure gets too low in an air brake system?
The brakes will be very sensitive.
Pressing and releasing the brake pedal unnecessarily can let air out faster than the compressor can replace it, reducing the available air pressure. If the air pressure in an air brake system gets too low, the brakes will no longer work.
24 . On flat surfaces, wheel chocks:
In situations where a driver cannot use a parking brake, wheel chocks can be used to hold a parked vehicle in place on a level surface.
25 . Dollies equipped with ABS are required to have malfunction lamps located where?
On the top
A dolly equipped with an Anti-Lock Braking System (ABS) is required to have a yellow malfunction lamp located on its left side.
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2025 South Carolina | Frequently Asked Questions
A CDL Class A license in South Carolina allows drivers to operate any combination of vehicles with a Gross Combination Weight Rating (GCWR) of 26,001 lbs or more, provided the Gross Vehicle Weight Rating (GVWR) of the vehicle(s) being towed is over 10,000 lbs. This typically includes tractor-trailers and truck and trailer combinations.
A Class A CDL license in South Carolina allows you to operate vehicles such as tractor-trailers, truck and trailer combinations, tank vehicles, livestock carriers, and flatbeds. It includes any combination of vehicles with a Gross Combination Weight Rating (GCWR) of 26,001 lbs or more where the towed vehicle(s) exceed 10,000 lbs GVWR.
To obtain a Class A CDL license in South Carolina, you must be at least 18 years old (21 for interstate driving), possess a valid South Carolina driver's license, pass a vision test, and successfully complete knowledge and skills tests. You must also provide proof of identity, Social Security number, South Carolina residency, and clear a medical examination.
In South Carolina, you must be at least 18 years old to qualify for a Class A CDL license for intrastate driving (within South Carolina only). However, if you plan to drive interstate (across state lines or transporting materials from out of state), you must be at least 21 years old.
Specific endorsements aren't required for a Class A CDL license but they can provide additional driving privileges. Endorsements include: H (Hazardous Materials), N (Tank Vehicles), P (Passenger Vehicles), S (School Bus), T (Double/Triple Trailers). To get an endorsement, you must pass additional written and skills tests related to the specific type of vehicle.
The Class A CDL skills test in South Carolina encompasses three main sections: pre-trip inspection, basic controls, and on-road driving. The pre-trip inspection tests your knowledge on vehicle safety. The basic controls test assesses your ability to maneuver and control the vehicle. The on-road driving test evaluates your ability to drive the vehicle in various traffic conditions.
Yes, there are limitations for Class A CDL license holders in South Carolina. These limitations or restrictions relate to the type of vehicle you can drive, safety equipment needed, and in some cases, the time of day you can drive. Restrictions are marked on your CDL and may be removed by passing additional tests.
In South Carolina, the written Class A CDL test is primarily offered in English. However, some locations may offer the test in Spanish. It's recommended to contact your local DMV office to confirm language availability. Please note, all drivers must still have a basic understanding of English to ensure road safety.
Yes, you can request accommodations for the Class A CDL written test in South Carolina if you have a disability. The South Carolina Department of Motor Vehicles (SCDMV) is committed to ensuring that its services are accessible to all individuals. However, specific accommodations depend on the nature of the disability and must comply with federal regulations regarding commercial driving safety.
Yes, if you fail the Class A CDL written test in South Carolina, you can retake it. You must wait at least one day before retaking the test. However, keep in mind there may be additional fees associated with each retest. It's recommended to study thoroughly before reattempting to increase your chances of passing.
