Tennessee CDL DMV Air Brakes 1

Before driving a vehicle with air brakes, you should ensure that the spring brakes come on automatically when air tank pressure falls to a level between 20 and 45 psi. You can do this by chocking the wheels and releasing air from the braking system by stepping on and off the brake pedal. Once the pressure drops to an unsafe level, the parking brake valve should pop out and spring brakes should come on.

If used and maintained properly, air brakes are a safe and effective way to stop large, heavy vehicles.

With some exceptions, you must have a tank endorsement to transport liquids or gases. This applies to both hazardous and non-hazardous substances.

In an air brake system, the air compressor is connected to the engine through gears or a v-belt.

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.

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.

A vehicle with air brakes must be equipped with a low air pressure warning signal. If the warning signal goes off while a vehicle is being driven, the driver should bring the vehicle to a complete stop and have the system repaired.

Vehicles equipped with Anti-Lock Braking Systems (ABS) have yellow malfunction lights to indicate issues in the braking system.

Air storage tanks are used to hold compressed air. The number and size of air tanks in an air brake system varies among vehicles.

If brakes are overused, they may overheat and stop working. This is referred to as brake fade.

It is important to know the maximum air loss rate that is safe for your specific vehicle. A single vehicle with air brakes should have a leakage rate no higher than 3 psi in a minute during an applied leakage test.

All trucks, truck tractors, and buses must be equipped with emergency brakes and parking brakes. Because air pressure can eventually leak away, emergency and parking brakes should be held on by mechanical force.

In a vehicle with air brakes, the brake lights are activated when the brake pedal is pushed and air pressure moves an electric switch. With the application of air pressure, the switch will then turn on the brake lights.

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. Tanks must be drained regularly to remove this build-up.

Spring brakes come on automatically when air pressure drops to an unsafe psi level. Instead of waiting for the spring brakes to automatically activate, you should safely exit the road as soon as you notice the low pressure warning signal and bring your vehicle to a stop while you are still able to control the brakes.

The stab braking method for emergency stops involves fully applying the brakes until they lock up. The brakes are then released until the wheels start rolling, and then the process is repeated.

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.

To make a normal stop in a vehicle with air brakes, push the brake pedal down. The harder the pedal is pressed, the more air pressure is released.

All air tanks on air-braked vehicles must have one-way check valves located between the air compressor and the first reservoir. This prevents air from flowing out in the event of a leak.

In a vehicle with air brakes, the brake lights are activated when the brake pedal is pushed and air pressure moves an electric switch. With the application of air pressure, the switch will then turn on the brake lights.

A wig wag is a type of low air pressure warning device in an air brake system. It drops a mechanical arm into the driver's view when the air pressure in the tanks falls below 60 psi.

The parking brake in a vehicle with air brakes should be used every time the vehicle is parked.

Front wheel braking is effective under all road conditions. It is unlikely that you will experience a front wheel skid, even on ice.

A one-way check valve is required to be between an air compressor and the first main reservoir. This valve prevents air from escaping the system if the air compressor develops a leak.

If your vehicle has air brakes, the air compressor drive belt should be checked before each drive. Check the tightness of the belt and verify that it is in good condition.