If this has ever happened to you, you will never forget it. You are driving along, minding your own business. Perhaps you have the windows rolled down and the radio up and you are happy with the world. And then you see a stop light, or a stop sign, or perhaps a car slowing up ahead, but as you go to put on your brakes, the unthinkable happens – nothing. Yes, the brakes aren’t working. And suddenly you are in a world of trouble.
Hopefully something that tense and dramatic has never happened to you. If it is, it’s possible you suffered a car accident, got a ticket, or perhaps merely had the terror (and later the expense) of realizing that your car’s brakes have failed. But you maintain your car, so why would something like this happen? Let’s examine your brake calipers. Brake calipers are a vital part of your car’s braking system and one culprit if things all go terribly wrong.
Brake calipers can be called one of your braking system’s most vital parts. Brake calipers are only used in cars with disc brakes, but as more and more cars come equipped standard with disc brakes – some only in the front, some in the front and back – brake calipers become more and more common and more and more important. If your car has a disc braking system, it means that your car’s wheels are attached to metal discs, or rotors. These metal discs spin right along with the wheels. Where your brake calipers come in is that they work to slow the car’s wheels by creating friction with the rotors.
The brake caliper is not exactly the same thing as the rotor, and in fact the they fit over each rotor like clamps. Your brake pads can be found inside each brake caliper. Brake pads are pairs of metal plates bonded with friction material. Your car will have outboard brake pads (which are on the outside of the rotors, facing toward the curb) and inboard brake pads (which are on the inside, toward the vehicle).
So what exactly happens when you step on the brake? Aside from actually stopping, of course! When you step on the brake, brake fluid works to create hydraulic (liquid) pressure, using the brake calipers to force the brake pads against the rotor. With the aforementioned high friction surface, brake pads serve to slow the rotor down or, if you wish, bring it to a complete stop. Because, as mentioned before, the rotor is attached to and spins right along with the wheel, this causes the wheels, and thus the car, to stop as well.
Brake calipers come in two main types – floating (or sliding) brake calipers and fixed brake calipers. The floating type of brake calipers move in and out relative to the rotor (hence, they are “floating”). They have one or two pistons positioned only on the inboard (near the car) side. These pistons push the entire brake caliper when the driver steps on the brakes. This creates friction on both sides of the rotor, allowing for quick stopping. Fixed brake calipers, unlike their floating counterparts, do not move. They have pistons arranged on both sides of the rotor. These fixed brake calipers are generally preferred by motor vehicle enthusiasts because they are thought to have higher levels of performance. But in most cars, they are not present simply due to their higher cost. Part of the reason for fixed brake caliper’s higher cost is that they often have two or more pairs of pistons arranged on both sides of each rotor. Some fixed brake calipers have as many as six pairs of pistons in all.