1. INTRODUCTION Foundation brakes are the most common air-brake systems found in trucks and buses and work the same way as in rail cars. Using the triple-valve principle, air builds up inside the brake pipes or air lines, releasing the brakes. Virtually the entire road going vehicles equipped with air brakes has a graduated release system where a partial increase in pressure dictates a proportional release in brakes.
The following components are exclusive to a foundation air-brake system in a truck or a bus:
• Air compressor: Pumps the air into storage tanks to be used in the brake system
• Air compressor governor: Controls the cut-in and cut-out point of the air compressor to maintain a set amount of air in the tank or tanks
• Air reservoir tanks: Hold compressed or pressurized air to be used by the braking system
• Drain valves: Release valves in the air tanks used to drain the air when the vehicle isn't in use
• Foot valve (brake pedal): When depressed, air is released from the reservoir tanks
• Brake chambers: Cylindrical container that houses a slack adjuster that moves a diaphragm or cam mechanism
• Push rod: A steel rod similar to a piston that connects the brake chamber to the slack adjuster. When depressed, the brakes are released. If extended, the brakes are applied.
• Slack adjusters: An arm connects the push rod to the…show more content… When a car is moving down the highway, it has a tremendous amount of stored energy in the form of inertia. To stop the car, the brakes convert kinetic energy into heat. When the driver pushes on the brake pedal, lever action pushes a rod into the brake booster and master cylinder. This produces hydraulic pressure in the master cylinder. Fluid flows through the brake lines to the brake assemblies. The brake assemblies use this pressure to cause friction for braking. Below are the basic parts that make up a modern brake