What is the main function of brake fluid in a braking system?

The main function of brake fluid in a braking system is to transfer force from the brake pedal to the various brake components. When the driver presses the brake pedal, this action creates hydraulic pressure in the brake lines filled with brake fluid. This pressure is then transmitted to the brake calipers or wheel cylinders, which engage the brake pads with the rotors or drums, ultimately slowing down or stopping the vehicle.

Brake fluid's ability to maintain a consistent and reliable hydraulic pressure is crucial for effective braking performance. It must also have properties like a high boiling point and low compressibility to handle the heat generated during braking without vaporizing or compressing, which could lead to brake failure. Each of the other options presents functions that do not align with the primary role of brake fluid in the braking system, thus highlighting the importance of understanding the specific properties and functions of brake fluid.