A brake caliper is a brake component fitted to each wheel and is activated by pressing the brake pedal; a piston within the caliper extends under hydraulic fluid pressure and forces a friction material known as brake pads against the spinning rotors in order to slow and stop a passenger vehicle.
While brake calipers started to become popular in Europe in late 1950, thanks to Jaguar and Dunlop racing, they didn’t become common in North America until 1970.
Where is a Brake Caliper Located?
A brake caliper is located at each wheel; however, while all passenger vehicles have brake calipers to the front, not all will have brake calipers fitted to the rear.
Some may use brake drums to the rear instead.
Brake calipers are fastened to the brake carrier, which is fastened to the suspension knuckle.
Broadly there are two types of brake calipers Fixed and Floating.
Floating calipers are by far the most common type of calipers fitted to cars today. They are so called because they employ piston(s) on one side of the caliper only, which, when activated, forces the caliper to slide (Float) across on slide pins and pull the opposing brake pad against the rotor.
Floating calipers are the most common type because they are comparatively inexpensive with little drop in performance when compared to the Fixed caliper.
The Fixed Caliper
Fixed caliper is used in many commercial vehicles and is commonly used in high-performance vehicles. Fixed calipers offer greater performance but cost a ton more, mostly because they employ more components.
As most regular passenger vehicles are fitted with floating calipers they are the calipers most folks will have. But you can check easily enough.
Wide-open spoked wheels allow a view of the caliper without removing the wheel or any other components.
Floating calipers will employ pistons on the inside of the caliper only.
Caliper components include Clip, Dust boot, Square cut piston seal, Piston Caliper body, Plastic/Nylon/Rubber bushings, Fastener slides, Dust cap, Bleed Valve, and dust cap.
Common Brake Caliper Problems
Brake calipers suffer from one main issue, piston seizure. All brake calipers employ at least one piston, which forces the pads against the rotor to slow and stop a vehicle. Brake systems with a poor record of brake fluid flushes are the most likely brake calipers to cause issues.
Brake fluid attracts moisture and, in doing so, protects the metal brake system components from corrosion, but there’s a limit to how much moisture fluid can handle. Fluid should be changed every three years; if this maintenance is skipped, rust begins to form on the piston, which often causes it to bind and eventually seize.
You may find the following pages helpful:
- About the Author
- Latest Posts
John Cunningham is an Automotive Technician and writer on Rustyautos.com. He’s been a mechanic for over twenty-five years and has worked for GM, Volvo, Volkswagen, Land Rover, and Jaguar dealerships.
John uses his know-how and experience to write fluff-free articles that help fellow gearheads with all aspects of vehicle ownership, including maintenance, repair, and troubleshooting.