WHAT DOES A HANDBRAKE ACTUALLY DO?
Gavin Winton
A car’s handbrake is the lever to a completely mechanical braking system which will bypass the primary hydraulic system if it fails. When the handbrake is applied, the brake cable passes through an intermediate lever to increase the force of your pull; this force is then split evenly between your brakes by an equaliser.
Typically, a mechanical lever is added to the existing disc or drum brakes on the car. In drum brakes, the handbrake cable runs directly to a lever on the brake shoes. In disc brakes an additional lever and corkscrew is added to the existing calliper piston. When the handbrake is pulled, the lever forces the corkscrew against the piston, which would normally be activated by the hydraulic foot pedal system.