The brake caliper is a U-shaped device with a piston or pistons on each side of the U. The brake pads are lined on the insides of the U and the brake disc goes inside the brake caliper. When the brakes are engaged, a high-pressure brake fluid is channeled from a master cylinder to the brake caliper where it activates the pistons. The pistons push the caliper into action and brake caliper clamps down on the brake disc. Friction stops the wheel from turning.
Your wheel spins at thousands of RPM and the brake caliper stops it. Imagine all the force and stress that it has to take up just to stop the wheel. Most of the heat generated from friction between the brake disc and the caliper is dissipated by the brake pads and the brake disc but the brake caliper has to endure most of the stress. Aside from the stress, there are also other factors that can lead to the demise of the brake caliper. There is also the brake fluid that can accumulate in the brake caliper that can cause rust. It can ultimately brake down the brake caliper for rust can breakdown the calipers strength until it cannot function properly.
It is always important to check your braking system and its component parts for it is your best safeguard against accidents. If your brake calipers are in need of replacing, always look for quality parts that perfectly fit your car's make.