CDL Air Brakes Endorsement II Practice

Air tanks should be drained daily to remove any accumulated moisture or condensation. This is important because moisture can cause corrosion and damage to the tank, as well as affect the performance of compressed air systems. Regularly draining the air tanks helps to maintain the quality and efficiency of the compressed air system.

Brakes can fade or fail due to overheating, which can occur when the brakes are used excessively or for prolonged periods. Low air pressure can also cause brake failure as it affects the proper functioning of the braking system. Additionally, not relying on the engine braking effect, which helps to slow down the vehicle by downshifting gears, can put excessive strain on the brakes and lead to their failure.

Leaving a vehicle unattended without applying parking brakes or chocking the wheels is not recommended. This is because it can lead to the vehicle rolling away, causing accidents or damage. Applying parking brakes or chocking the wheels helps to ensure that the vehicle remains stationary and does not pose a risk to others or property. Therefore, the correct answer is "No."

A dual air brake system refers to a braking system in which there are two separate systems for operating the front and back brakes of a vehicle. This setup allows for better control and braking power, as each system can be independently adjusted and controlled. By having separate systems for the front and back brakes, the vehicle can maintain stability and prevent skidding during braking maneuvers.

To check if the spring brakes come on automatically, you should step on and off the brake with the engine off. If the parking brake knob pops out when the air pressure falls between 20-40 psi, it indicates that the spring brakes are functioning correctly.

The statement is false because even if you are away from your vehicle for a short time, it is still necessary to use the parking brake. The parking brake is designed to hold the vehicle in place and prevent it from rolling, especially on inclines or uneven surfaces. Failing to engage the parking brake can result in the vehicle moving unexpectedly, causing damage or injury. Therefore, it is important to always use the parking brake whenever leaving a vehicle unattended, regardless of the duration.

If oil and water collect in the air tanks, it can cause the brakes to fail. Oil and water can contaminate the brake system, leading to a loss of brake pressure and reduced braking effectiveness. This can result in the brakes not being able to generate enough force to stop the vehicle, increasing the risk of accidents and loss of control. Therefore, it is important to regularly maintain and drain the air tanks to prevent the accumulation of oil and water.

The purpose of an alcohol evaporator is to reduce the risk of ice in the brake valves and other parts in cold weather. This device helps prevent the formation of ice by evaporating alcohol into the air system, which lowers the freezing point of any moisture present. By reducing the risk of ice formation, the evaporator helps maintain the proper functioning of the brake valves and other components, ensuring the safety and efficiency of the braking system in cold weather conditions.

To check the slack adjuster, it is necessary to park the vehicle on level ground and turn off the parking brakes. Then, one needs to pull hard on each slack adjuster. If the slack adjuster moves more than one inch, it indicates that it is not properly adjusted and requires attention.

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When driving on a long steep downgrade, the engine alone may not provide enough braking power to slow down or stop the vehicle. Therefore, the use of brakes becomes necessary to supplement the engine's braking effect. This means that the statement "The use of brakes on a long steep downgrade is only a supplement to the braking effect of the engine" is true.

The slack adjusters are not the space between the back wheels or an adjusting nut under the cab to adjust the springs. The correct answer is that slack adjusters are an adjusting nut on the backside of the brake drum used for adjusting the brakes. This nut is responsible for maintaining the proper tension on the brake shoes, ensuring that they make proper contact with the drum to effectively stop the vehicle.

The maximum leakage rates are less than two psi in one minute for single vehicles and less than three psi in one minute for combination vehicles. This means that the air pressure in the tires should not decrease by more than two psi in one minute for single vehicles and three psi in one minute for combination vehicles. Any leakage rate exceeding these limits would be considered excessive and could indicate a problem with the vehicle's tires or air system.

Being in the proper gear before starting down a hill allows you to control your speed more effectively. By being in the correct gear, you can take advantage of engine braking, which helps to slow down the vehicle without relying solely on the brakes. This means that you only need to apply the brake lightly to feel a definite slowdown, reducing the risk of overheating the brakes or losing control of the vehicle. Shifting gears while going downhill can be risky and may cause a loss of control, so it is best to be in the proper gear before starting the descent.

Squeeze braking is another name for controlled braking. This term refers to the technique of gradually applying pressure to the brakes in a smooth and controlled manner, rather than abruptly slamming them on. This allows for better control of the vehicle and reduces the risk of skidding or losing control.