FAQ: Youtube How To Do A Static Brake Test On A School Bus?

How do you test 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 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).

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Which three tests should you perform on a hydraulic brake system?

To test hydraulic brakes, you should pump the brake pedal three times, then apply firm pressure to the brake pedal and hold for five seconds. The pedal should not move. If it does, there may be a leak. 23.43 % of our users get this question wrong.

What is a static brake check?

Test Air Leakage Rate (Static check) With a fully-charged air system (typically 120 psi), turn off the engine, chock the wheels, release (push in) the parking brake button (all vehicles) and trailer air supply button (for combination vehicles) and time the air pressure drop.

What is maximum leakage rate?

6. What are the maximum leakage rates? Less than four psi in one minute for single vehicles and less than eight psi in one minute for combination vehicles. Less than two psi in one minute for single vehicles and less than three psi in one minute for combination vehicles.

What is the first step of the air brake test?

Before starting the air brake test, park the vehicle on a flat surface, apply spring brakes and wheel chokes. Start testing with the low air warning device.

What are the five basic components of an air brake system?

5 Basic Components of an Air Brake System in Trucks

  • Air compressor.
  • Reservoirs.
  • Foot valve.
  • Brake chambers.
  • Brake shoes and drums.

How do you start an air brake on a truck?

How to Release Air Brakes

  1. Start the truck by turning the ignition key to the “Start” position.
  2. Locate the air pressure gauge on the dash.
  3. Observe the needle in the air pressure gauge as it rises while the truck is idling.
  4. Allow the air pressure to build to 120 pounds of air.
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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.

What is the first thing you should do when a low air pressure warning comes on?

The first thing to do when a low air pressure warning comes on is: Stop and safely park as soon as possible. The braking power of the spring brakes: Depends on the adjustment of the service brakes.

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.

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