South Carolina CDL DMV Endorsement Double 1

A driver should inspect wheels before a drive, specifically looking for damage on the wheels and rims. Wheels or rims that have had welding repairs are not safe for use.

Backing is always dangerous because it is impossible to see everything that is behind your vehicle. Only drive in reverse if it is absolutely necessary.

When backing up to couple a trailer, you should position the tractor directly in front of the trailer. Trying to couple while backing at an angle could cause the trailer to move and the landing gear to break.

When inspecting your vehicle's suspension, verify that leaf springs do not have missing or broken leaves. If at least one-fourth of the leaves in a leaf spring are missing, the vehicle will be put out-of-service until the defect is fixed.

Compressed air in an air brake system usually contains a certain amount of water and compressor oil. The water and oil can damage the brakes if left to accumulate in the system. Manually operated air tank drains must be opened daily to remove this build-up.

The most common type of foundation brake is an s-cam drum brake.

When inspecting the convertor dolly, ensure that all components are present and in proper working condition. Be sure to check the upper and lower fifth wheel, the air lines, and the electric lines. The air lines should be securely attached to the proper glad hands and should not contain any leaks. They should be attached with enough slack to allow easy turning.

In conditions of poor visibility (such as at dawn, at dusk, in rain, or in snow), you should turn on your low beam headlights to make your vehicle easier to see. Do not use your high beams when driving near other vehicles.

Problems to check for when inspecting tires include: air pressure that is too low or too high; using radial and bias-ply tires together; tread depth of less than 4/32 of an inch in major grooves on front tires; and tread depth of less than 2/32 of an inch on all other tires.

When inspecting a vehicle, you should check for required emergency equipment, including at least one fire extinguisher.

When driving under foggy conditions, lights cannot be taken as a reliable indication of where the road is. The lights may be coming from a vehicle that has pulled off the road.

Most heavy vehicles with unsynchronized manual transmissions require double clutching to change gears.

In an air brake system, there are three different braking systems: a service brake system, a parking brake system, and an emergency brake system. The emergency brake system uses parts of both the parking and service brake systems.

Because air expands when hot, tire pressure increases as temperatures increase. This can sometimes result in tire failure. Consistently check your tire pressure when making a trip in hot weather.

Vehicles with Anti-Lock Braking Systems (ABS) have yellow malfunction lamps.

Anti-Lock Braking Systems (ABS) will help you to maintain control during hard braking. ABS will not necessarily shorten your stopping distance.

Air expands as it gets warmer, so the air pressure in your tires could reach dangerously high levels while being used in very hot weather. If this happens, stop and let your tires cool. Do not let air out of the tires, as this could result in the pressure dropping to an unsafe level once the tires cool down.

When operating a double or triple, the shut-off valves at the rear of the last trailer should be closed. All other shut-off valves should be open.

It is important that all of a vehicle's equipment is in proper working condition before beginning a trip. If a trailer's spring brakes do not release when you push in the tractor air supply control, you should make sure the air line connections are properly attached and sealed.

It is important to inspect your tires before every drive. Rust around wheel nuts may indicate that they are loose.