In a hydraulic brake system, what component serves as the reservoir for brake fluid?

In a hydraulic brake system, the master cylinder acts as the reservoir for brake fluid. This component is critical because it stores the hydraulic fluid necessary for the brake system to function properly. When the driver presses the brake pedal, the master cylinder generates hydraulic pressure by pushing the brake fluid through the brake lines to the brake calipers, which then engage the brake pads with the brake rotors.

The master cylinder is equipped with a reservoir that holds excess brake fluid to ensure that the system remains filled and functioning. This design allows for changes in fluid volume caused by temperature variation and brake wear without introducing air into the hydraulic system, which could compromise braking performance.

The other components mentioned do play important roles in the braking system but do not serve as fluid reservoirs. For example, the brake caliper is responsible for clamping the brake pads onto the rotors to create friction, while the brake booster amplifies the force applied by the driver to the brake pedal, making it easier to stop the vehicle. The pressure regulator helps manage the hydraulic pressure but does not store brake fluid itself.