- 1 What is a spring brake valve?
- 2 What is the purpose of a spring brake modulator valve?
- 3 When the spring brakes are on you should never?
- 4 How does a spring brake inversion valve work?
- 5 What is stab braking?
- 6 What is spring brake priority?
- 7 Why are spring brakes a reliable type of parking brake?
- 8 Why should you avoid compounding the brakes?
- 9 What is the purpose of relay valve?
- 10 What are spring brakes held back by?
- 11 How should you check that your service brakes are working properly?
- 12 How do I know if my spring brakes come on automatically?
- 13 What does an air brake inversion valve do?
- 14 What is an anti compounding valve?
What is a spring brake valve?
A spring brake control valve is normally a push/pull type valve fitted with a yellow, four-sided knob located near the driver (See diagram 4-3). Most spring brake control valves are pushed to supply air and release the spring brakes, then pulled to exhaust air and apply the spring brakes.
What is the purpose of a spring brake modulator valve?
Used on some vehicles with dual air systems. This device provides a means of using the force of the spring brakes to assist in stopping a vehicle in an event of a failure in the rear (primary) air system.
When the spring brakes are on you should never?
Use the parking brakes whenever you park. Caution. Never push the brake pedal down when the spring brakes are on. If you do, the brakes could be damaged by the combined forces of the springs and the air pressure.
How does a spring brake inversion valve work?
A pneumatic brake system employing dual-diaphragm, spring -actuated, air-released brake actuators is provided with an inversion valve which, in the event of a brake system failure, prevents the brakes from being automatically applied while permitting controlled brake application by releasing compressed air from each
What is stab braking?
Stab braking: Release the brakes when the wheels lock up. As soon as the wheels start rolling, put on the brakes fully again. It can take up to 1 second for the wheels to start rolling after you release the brakes.
What is spring brake priority?
This means that, in a system with “ spring brake priority,” the air from the towing vehicle first fills the air tank for the spring brakes to a certain pressure before filling the air tank for the service brakes. Trailers with spring brake priority can be towed without waiting for the service brake air tanks to fill.
Why are spring brakes a reliable type of parking brake?
Spring brakes are often installed on both rear axles in a tandem-axle unit. They are a reliable parking brake because they are held on by spring pressure and require no air. The front chamber is essentially a service- brake chamber, and is used to perform the service- brake function.
Why should you avoid compounding the brakes?
CAUTION: Compounding the brakes happens when a service brake application is made with the park brake still applied. This can result in damaged brake components and possibly brake failure. To avoid compounding, the park brake should be released before a foot brake application is made.
What is the purpose of relay valve?
A relay valve is an air-operated valve typically used in air brake systems to remotely control the brakes at the rear of a heavy truck or semi-trailer in a tractor-trailer combination.
What are spring brakes held back by?
Spring brakes are usually used to meet these needs. When driving, powerful springs are held back by air pressure. If the air pressure is removed, the springs put on the brakes. A parking brake control in the cab allows the driver to let the air out of the spring brakes.
How should you check that your service brakes are working properly?
How should you check that your service brakes are working properly? Wait for normal air pressure, release the parking brake, move the truck forward slowly, and apply the brake pedal firmly. The braking power of the spring brakes: Depends on the services brakes being in adjustment.
How do I know if my spring brakes come on automatically?
What can you check to see if the spring brakes come on automatically? Step on and off the brake, with the engine off, the parking brake knob should pop out when air pressure falls between 20-40 psi. Get under the vehicle and pull on the spring brakes. Turn on the engine and pump the brake pedal down to the floor.
What does an air brake inversion valve do?
The inversion valve is closed by using air pressure from another source and is primarily used in emergency or parking brake systems which operate with air from an isolated reservoir.
What is an anti compounding valve?
An anti – compounding valve in the system design helps prevent the application of both the spring and service brakes together. Emergency Braking. In emergency situations where system air pressure is reduced or lost, government regulations require vehicles to meet specified stopping distances.