Knowledge Of Air Brakes

When a low air pressure warning comes on, the first thing you should do is stop and safely park as soon as possible. This is because low air pressure can greatly affect the braking system of a vehicle, making it unsafe to continue driving. Adjusting the brake pedal for more travel or opening the air supply control valve may not address the underlying issue causing the low air pressure warning, and it is crucial to prioritize safety by stopping and parking the vehicle to prevent any potential accidents or further damage.

In air brake vehicles, the parking brakes should be used any time the vehicle is parked. This is because the parking brakes are designed to hold the vehicle in place and prevent it from rolling or moving when it is not in use. Using the parking brakes whenever the vehicle is parked ensures that it remains stationary and does not pose a safety risk.

A supply pressure gauge is used to measure the amount of pressure present in a system. In this case, the answer states that the supply pressure gauge tells you how much pressure is in the air tanks. This means that the gauge is specifically designed to measure the pressure in the air tanks and not in any other component such as the tractor brake lines or the trailer brake line. Therefore, the correct answer is air tanks.

The brake pedal in an air brake system controls the air pressure applied to put on the brakes. This means that when the driver presses the brake pedal, it activates the air pressure system, which then applies the necessary pressure to engage the brakes and slow down or stop the vehicle. By controlling the air pressure, the brake pedal allows for precise control over the braking action, ensuring the vehicle can be brought to a safe stop.

It is never okay to leave your truck unattended without applying the parking brake or chocking the wheels. This is because doing so can result in the truck rolling away, causing accidents or damage to property. It is important to always ensure that the truck is secure before leaving it unattended to prevent any potential hazards.

If the low air pressure warning comes on for only one system in a dual air brake system, it is important to stop and safely park the truck or bus. Continuing to drive without fixing the system can lead to brake failure and potential accidents. Therefore, the correct course of action is to wait until the system is fixed before continuing the journey.

Whenever you leave the vehicle unattended, the parking brakes should be used. This is important to ensure that the vehicle remains stationary and does not roll away. The parking brakes provide an additional level of safety, especially for air brake vehicles, which may require more time to build up air pressure before the brakes can be fully engaged. Using the parking brakes whenever the vehicle is unattended helps prevent accidents and ensures the vehicle remains in place.

If the alcohol evaporator in an air brake system is not kept filled with alcohol, ice may form in the air storage tanks. This can cause the brakes to fail because the ice can block the flow of air through the system, preventing the brakes from properly engaging and disengaging. This can lead to a loss of braking power and potentially dangerous situations on the road.

The S-cam drum is the most common type of foundation brake found on heavy vehicles. This type of brake utilizes a rotating S-shaped cam to push the brake shoes against the drum, creating friction and stopping the vehicle. The S-cam drum brake system is known for its durability and effectiveness in heavy-duty applications, making it the preferred choice for heavy vehicles. The other options, such as the disc brake and wedge drum, are less commonly used in this context.

When the spring brakes are engaged, it means that the brakes are already applied automatically. Therefore, there is no need to push the brake pedal as it will not have any effect. Pushing the brake pedal while the spring brakes are on can potentially damage the braking system.

The modern air brake system consists of three different systems: the service brake, the parking brake, and the emergency brake. The emergency brake is a crucial component of the system as it provides an additional braking mechanism in case of emergencies or sudden stops. It allows the driver to quickly apply maximum braking force to bring the vehicle to a halt in critical situations. Therefore, the correct answer is "emergency."

When you apply the brakes, the brake shoes/linings are pressed against the brake drum. This is because the brake drum is a rotating component attached to the wheel, and when the brakes are engaged, the brake shoes or linings are pushed against the inner surface of the drum, creating friction and causing the wheel to slow down or stop. The S-cam and slack adjuster are components of the braking system that help to control the movement and positioning of the brake shoes, but they do not directly come into contact with the drum. Therefore, the correct answer is the brake drum.

The brake system that applies and releases the brakes when the driver uses the brake pedal is known as the service brake system. This system is responsible for the normal braking function of a vehicle, allowing the driver to slow down or stop the vehicle when necessary. The emergency brake system, also known as the parking brake system, is a separate system that is used to hold the vehicle in place when parked or during an emergency situation. Therefore, the correct answer is service.

An air supply pressure gauge is a crucial component in air brake equipped vehicles as it allows the driver to monitor the pressure of the air supply in the braking system. This gauge helps ensure that the air pressure is within the appropriate range for optimal braking performance. By constantly monitoring the air supply pressure, the driver can detect any abnormalities or leaks in the system, allowing for timely maintenance and repairs. Therefore, it is essential for all air brake equipped vehicles to have an air supply pressure gauge.

The air compressor governor controls the release of air into the air storage tanks. As air is pumped into the tanks, the governor regulates the speed of the air compressor to maintain a consistent pressure. This pressure is then applied to the brakes, allowing for effective braking in vehicles. Therefore, the correct answer is "when air is pumped into the air storage tanks."

The correct answer is "check and fill the alcohol level." If your vehicle has an alcohol evaporator, it is important to regularly check and maintain the alcohol level. This is because the alcohol evaporator helps to prevent the fuel system from freezing during cold weather. By checking and filling the alcohol level, you ensure that the evaporator is functioning properly and that your vehicle's fuel system is protected from freezing.

The parking or emergency brake on a heavy vehicle can only be held in position by something that cannot leak away. Spring pressure is a reliable and effective method to hold the brake in position because springs do not rely on external factors like air pressure or hydraulic pressure, which can potentially leak or fail. Springs provide a constant force to keep the brake engaged, ensuring the vehicle remains stationary and safe.

The correct answer is "turns on the brake lights to warn drivers behind you." The stop light switch is responsible for activating the brake lights when the driver applies the brakes. This alerts drivers behind the vehicle to slow down or stop, ensuring their safety and preventing accidents.

If the truck has a dual air brake system and one of the systems is low on pressure, it means that there is insufficient pressure to fully engage the brakes on either the front or rear wheels. As a result, either the front or rear brakes will not be fully operational, leading to decreased braking efficiency and potentially compromising the safety of the vehicle.

The braking power of the spring brakes depends on the service brakes being in adjustment. This means that if the service brakes are not properly adjusted, it can affect the braking power of the spring brakes. Therefore, it is important to ensure that the service brakes are in proper working condition and adjusted correctly in order to maintain the effectiveness of the spring brakes.

The correct answer is "spring". In trucks and buses, the parking or emergency brakes can be legally held on by spring pressure. This means that the brakes are engaged and held in place by the force exerted by a spring, rather than by air pressure or fluid pressure.

If your truck or bus has dual parking control valves, you can use pressure from a separate tank to release the spring emergency/parking brakes to move a short distance. This means that instead of relying on the service air pressure to release the brakes, you can use the pressure from a separate tank. This can be useful when you need to move the vehicle a short distance without using up the service air pressure.

During normal driving, spring brakes are usually held back by air pressure. Air pressure is used to keep the spring brakes disengaged so that the vehicle can move freely. When the air pressure is released, the spring brakes engage and apply pressure to the brakes, stopping the vehicle. This system ensures that the brakes are only activated when needed and allows for smooth and efficient driving.

The application pressure gauge shows how much air pressure you are applying to the brakes. This gauge is used to monitor the amount of pressure being exerted on the brake system, allowing the driver to ensure that the brakes are being applied with the appropriate force. By observing the application pressure gauge, the driver can adjust their braking technique to ensure optimal braking performance and safety.

Before driving a truck or bus with a dual air brake system, the pressure in each system should be at least 100 psi. This ensures that there is enough pressure to effectively engage the air brakes and provide sufficient stopping power for the vehicle. Having the correct pressure in each system is crucial for safe operation and compliance with regulations.

Driving a vehicle with brake drums or discs that have cracks or are thinner than the manufacturer's specifications is unsafe because it can compromise the braking system's effectiveness. This can lead to reduced braking power, longer stopping distances, and potentially even brake failure. Therefore, it is important to ensure that brake drums or discs are not cracked and meet the manufacturer's recommended thickness, which is generally 1/4 inch.

Under normal conditions, to engage the parking brake, the driver must let the air out of the spring brakes. This is because the parking brake in a commercial vehicle is typically controlled by the spring brakes, which are part of the air brake system. Releasing the air from the spring brakes allows the brakes to engage and hold the vehicle in place when parked. It is important to ensure that the air brake system is fully pressurized and the engine is turned off before engaging the parking brake, but these steps are not directly related to letting the air out of the spring brakes.

The S-cam pulls the brake shoes away from the drum and allows the wheels to roll freely. This is because when the brake pedal is released, the S-cam rotates and pushes the brake shoes away from the drum, releasing the pressure and allowing the wheels to rotate without any friction. This action is essential for the smooth operation of the brakes and enables the vehicle to move freely.

The modulating control valve allows you to control the amount of air pressure in the brake system. This means that it can regulate the pressure going to the spring brakes, which are a type of brake used in heavy vehicles. Therefore, the correct answer is "spring brakes" because the modulating control valve is responsible for controlling the air pressure in these brakes.