The brake pads are designed for high friction with brake pad material embedded in the disc in the process of bedding while wearing evenly. The brake pad is pressed against the brake rotor to stop the vehicles wheel from turning. The brake pads must usually be replaced regularly depending on brake pad material, and most are equipped with a method of alerting the driver when this needs to take place. Some have a thin piece of soft metal that causes the brakes to squeal when the pads are too thin, while others have a soft metal tab embedded in the pad material that closes an electric circuit and lights a warning light when the brake pad gets thin. More expensive cars may use an electronic sensor. Brake pads should always be replaced in pairs.
