- 1 How do you check air brakes on a school bus?
- 2 How do you use air brakes on a bus?
- 3 What kind of brakes does a school bus have?
- 4 What is a slack adjuster on a school bus?
- 5 What is the 7 step air brake test?
- 6 What PSI level is the safety relief valve set to open at?
- 7 When spring brakes are on you should never?
- 8 What’s stab braking?
- 9 What is a service brake on a school bus?
- 10 What kind of brakes do buses use?
- 11 What are the five basic components of an air brake system?
- 12 What causes air brakes to stick?
- 13 How does air brake chamber work?
How do you check air brakes on a school bus?
Start the bus and let the air pressure build to at least 90 psi. Step on the brake pedal and put the bus into gear. Slowly take your foot off the brake and gently press the accelerator. The bus should not move.
How do you use air brakes on a bus?
To apply the air brakes during normal stops, push the brake pedal down. Control the pressure so the vehicle comes to a smooth, safe stop. If you have a manual transmission, do not push the clutch in until the engine RPM is down close to idle. When stopped, select a starting gear.
What kind of brakes does a school bus have?
All school buses shall be manufactured with a parking brake system of a functional type with a solely mechanical means to retain engagement.
What is a slack adjuster on a school bus?
All automatic slack adjusters adjust the brakes during the low air pressure portion of a brake application in the range of 20 psi or less. Each method can be affected by wear in the foundation brake. Adjusting at low pressure allows the air chamber, shoe return springs and S-cam to work together.
What is the 7 step air brake test?
The Seven-Step Air Brake check is designed to test the governor cut-in and cut-out pressures, air pressure leakage, warning buzzer, brake valves and air pressure rebuild rates. Brakes off means the yellow and/or red valve is pushed in (on = valve out).
What PSI level is the safety relief valve set to open at?
A safety relief valve is installed in the first tank the air compressor pumps air to. The safety valve protects the tank and the rest of the system from too much pressure. The valve is usually set to open at 150 psi.
When spring brakes are on you should never?
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.
What’s stab braking?
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.
What is a service brake on a school bus?
The service system that is used for normal braking. The emergency/parking system which, as the name implies, is used in an emergency and for parking. The air compressor. The heart of the air brake system is the compressor, which is often directly coupled to the engine.
What kind of brakes do buses use?
Air brakes are typically used on heavy trucks and buses. The system consists of service brakes, parking brakes, a control pedal, and an air storage tank.
What are the five basic components of an air brake system?
5 Basic Components of an Air Brake System in Trucks
- Air compressor.
- Foot valve.
- Brake chambers.
- Brake shoes and drums.
What causes air brakes to stick?
Binding trailer air brakes are often caused by the hand brake valve not delivering enough air pressure through to the trailer control valve to balance it off. Sticking or seized brake valve or foundation brake linkages.
How does air brake chamber work?
Air brake chambers are round metal containers, located at each wheel, where compressed air is converted into mechanical force to apply the brakes and stop the vehicle. The motion of the slack adjuster transfers to the brake assembly, causing the brake shoes or pads to make contact with the brake drum or disc.