Vacuum brakes are a type of braking system that uses the vacuum created by the engine to help apply the brakes.
When the brake pedal is pressed, a valve opens and allows air to enter the brake cylinder. This reduces the vacuum in the cylinder, which creates a pressure difference between the top and bottom of the piston. The piston is then forced upwards, which applies the brakes.
When the brake pedal is released, the valve closes and the vacuum in the cylinder is restored. This allows the piston to return to its original position, which releases the brakes.
How Vacuum Brakes Work in Detail
The vacuum brake system consists of the following components:
- Brake pedal
- Vacuum reservoir
- Brake cylinder
- Ball valve
- Brake rigging
When the brake pedal is pressed, the vacuum reservoir is connected to the brake cylinder. This allows the vacuum in the reservoir to be transferred to the brake cylinder.
The ball valve then closes, preventing the vacuum in the brake cylinder from being lost. This creates a pressure difference between the top and bottom of the piston.
The piston is then forced upwards, which applies the brakes.
When the brake pedal is released, the ball valve opens and the vacuum in the brake cylinder is restored. This allows the piston to return to its original position, which releases the brakes.
Questions and Answers
How does a vacuum brake work without the engine running?
A vacuum brake will not work without the engine running. This is because the vacuum is created by the engine.
What are the advantages of vacuum brakes?
Vacuum brakes have a number of advantages, including:
- They are lightweight and easy to install.
- They are very efficient, requiring less effort from the driver to apply the brakes.
- They are less likely to fade than other types of brakes.
What are the disadvantages of vacuum brakes?
Vacuum brakes have a few disadvantages, including:
- They can be affected by leaks in the vacuum system.
- They are not as effective in cold weather.