A disc-brake system uses calipers, which are hydraulically operated to squeeze the rotors (via brake pads) to stop the vehicle. The caliper shown here is being removed from an '87 El Camino (G-body) and is a single-piston floating design. With this style, a single piston is mounted inside the inboard side of the caliper, and as the driver applies pedal pressure, hydraulic fluid originating from the master cylinder forces the caliper piston outward against the inner brake pad toward the inner side of the rotor. At the same time, the caliper housing (sliding side-to-side across two large locating pins) moves in a counteracting direction from the caliper piston, forcing the outer brake pad toward the rotor. The simultaneous action of the pads slows or stops the vehicle.