Alabama CDL DMV Air Brakes 1

If a tractor is equipped with an Anti-Lock Braking System (ABS) but the trailer is not, the risk of jackknifing will be reduced and the driver should still be able to maintain steering control. If only the trailer is equipped with ABS, it is less likely that the trailer will swing out to one side.

An alcohol evaporator can help prevent ice from building up in an air brake system. In cold weather, the evaporator should be checked and refilled every day.

Air brakes consists of three separate braking systems: the service brake system, the parking brake system, and the emergency brake system. The service brake system applies and releases the brakes when you use the brake pedal while driving normally.

Always apply the parking brake when leaving your vehicle unattended.

Friction inside a brake drum is caused when the brake shoes and linings push against the inside of the drum. The friction in the drums will slow and stop the vehicle.

Never apply the brake pedal if your spring breaks are activated. Brakes can be damaged if they are subject to both springs and air pressure.

If a vehicle is equipped, an application pressure gauge shows how much air pressure is being applied to the brakes. This gauge can help a driver identify if their brakes are beginning to fade.

Before a trip, you should check each slack adjuster after parking, setting wheel chocks, and disengaging the parking brake. Pull the slack adjusters to make sure that they do not move more than about one inch from where the push rod is attached. If they move more than one inch, they may be out of adjustment and will need to be fixed.

The air storage tanks in an air brake system store compressed air to be used for braking. They hold enough air for the brakes to still be used several times if the compressor stops working.

In general, you should always use the parking brake when parking your vehicle. However, you should not apply the parking brake if your brakes are very hot or if your brakes are wet and temperatures are below freezing.

When inspecting a vehicle with a dual air brake system, you should wait for air pressure to build from 85 to 100 psi in both the primary and secondary systems. This should take about 45 seconds.

On a long or steep downgrade, brakes should only be used to supplement the braking effect of the engine. Apply the brakes just enough to feel a definite slowing down, then release them once you are about 5 mph below your target "safe" speed. Once your vehicle reaches its safe speed again, repeat this process.

Some air brake systems contain an alcohol evaporator. An evaporator introduces alcohol into the system to help inhibit the formation of ice in cold weather.

In an air brake system, air tanks have drains to remove accumulations of water and compressor oil. Allowing water and oil to accumulate in the system could cause damage to the brakes.

In an air brake system, a low air pressure warning signal must come on if air pressure in the tanks falls below 60 psi. This warning signal may come in the form of a light, a buzzer, or a wig wag.

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

An air brake system's safety relief valve is located in the tank that is first to receive air from the compressor.

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

ABS is equipped in addition to a vehicle's normal braking system and it neither increases nor decreases the vehicle's braking capability. ABS activates during hard applications of the brake pedal in order to prevent wheels from locking up.

A vehicle's total stopping distance is made up of perception distance, reaction distance, brake lag distance, and braking distance. With all of these factors included, an air brake-equipped vehicle traveling at a speed of 55 mph under ideal driving conditions will need approximately 450 feet to come to a complete stop.

Do not use the brake pedal when the spring brakes are on. This could damage the brakes by subjecting them to the combined forces of springs and air pressure.

Vehicles with ABS have yellow malfunction lamps to alert drivers when the braking systems are not working. Be sure you know where the malfunction lamp on your vehicle is before beginning a trip.

When a brake pedal is pressed and the S-cam is turned, the S-cam presses the brake shoes against the inside of the brake drum. This causes friction and will cause the vehicle to slow.

Both systems in a dual air brake system share a single air compressor. If the air compressor is damaged, neither system will be able to operate properly.

If equipped, ABS is in addition to a vehicle's normal braking system and does not increase or decrease the braking power of any other system. ABS only activates when a vehicle's wheels are about to lock.