How does a duo servo drum brake assembly work work?

A duo servo drum brake assembly operates by using two brake shoes that are mounted within a drum. When the brake pedal is pressed, hydraulic pressure pushes the shoes outward against the inner surface of the drum. The leading shoe exerts a self-servo action, causing it to pull the trailing shoe into greater contact with the drum, enhancing braking force. This design allows for more effective and efficient braking, especially under heavy loads.