What component is responsible for stopping the vehicle when air brakes are applied?

The brake chambers are integral to the functioning of air brakes because they convert the compressed air pressure into mechanical force that engages the brakes. When the driver applies the brake pedal, air from the compressor travels through the system and fills the brake chambers. This air pressure pushes a diaphragm within the chamber, which then moves the push rod. The movement of the push rod activates the brake shoes or pads, pressing them against the brake drum or rotor to slow down or stop the vehicle.

In contrast, the air compressor generates air pressure for the braking system but does not directly stop the vehicle. The air dryer removes moisture and contaminants from the compressed air to maintain system efficiency but is not involved in the braking action. The relay valve helps control the air flow to the brake chambers but is not the component that directly applies the brake force. Thus, it is the brake chambers that are directly responsible for stopping the vehicle when air brakes are applied.