How are the wheel brakes activated in an air brake system?

In an air brake system, the wheel brakes are activated by air pressure pushing the brake shoes against the brake drum. This process is fundamental to how air brakes function. When the driver presses the brake pedal, it sends a signal to the air compressor to increase air pressure within the system. This increased pressure is then routed to the brake chambers located at each wheel. Inside these chambers, the air pressure pushes the diaphragms, which in turn move the brake shoes against the inner surface of the drum, creating the necessary friction to slow down or stop the vehicle.

The use of air pressure is particularly advantageous in larger vehicles, such as trucks and buses, where hydraulic systems might struggle to provide the necessary force. Air brake systems allow for greater braking power and reliability, which is essential for safely handling large loads or steep descents. Understanding this mechanism is crucial for drivers as it ensures they are equipped to handle their vehicles safely and effectively in various driving conditions.