What does the wheel cylinder do in a hydraulic brake system?

In a hydraulic brake system, the wheel cylinder plays a crucial role in the operation of drum brakes. Specifically, the wheel cylinder is responsible for expanding the brake shoes against the inside of the brake drum. When hydraulic pressure is applied to the wheel cylinder, it pushes the pistons outward, which subsequently forces the brake shoes to contact the drum. This contact creates the necessary friction to slow or stop the vehicle.

Understanding the function of the wheel cylinder clarifies how it is an essential component of the braking process in drum brake systems. The interaction between the hydraulic pressure and the expansion of the brake shoes is what allows for effective braking action, making the wheel cylinder a critical element in the overall functionality of hydraulic brakes.