Arguably the key component of your car's brake system, the brake caliper operates just like a small hydraulic clamp designed to grip the brake rotor and bring your car to a halt. If you?ve ever seen or worked on a brake caliper, you know what we're talking about. The brake caliper is a U-shaped device with a piston or pistons on one or both sides of the U. The brake pads ride on top of the brake caliper pistons, and the rotor spins in the channel of the U. When you hit the brakes, high-pressure fluid is channeled from the master cylinder down to the brake caliper where it pushes the piston or pistons inward. That brake caliper action moves the pads against the spinning brake rotor, and the friction stops your vehicle. Since the brake caliper is affixed to your vehicle frame and the rotor is spinning and hundreds of RPM, it's easy to imagine the massive forces that the brake caliper has to absorb. Much of the heat energy is dissipated by the rotor and pads (which is why they're replaced the most), but the pulling and twisting forces the brake caliper has to endure require that it be extremely strong. More than anything else, though, it's the hydraulic brake fluid that leads to the demise of a brake caliper. If it's not changed often enough, moisture in the fluid will begin to rust out the inside of your brake caliper, resulting in leaks and sticking pistons. Eventually the brake caliper will cease to function altogether, significantly diminishing your car's stopping ability. The problem is, you may not even realize when you have a bad brake caliper if you're not paying attention to how your car drives. So make sure you're attuned to any pulling, squealing, or leaks that may come from a bad brake caliper. If and when you find a problem, replace the brake caliper immediately with a high-quality new or remanufactured brake caliper.