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
