What do brake rotors do?
When most people say their car’s brakes are out, they are referring to the brake pads. It takes a lot of work to stop a couple tons of metal, especially when coming to a screeching halt. Unbeknownst to many, there is another crucial component of your vehicle’s braking system, one that works directly in conjunction with the pads. These are called the rotors, and they are the discs that attach to the wheel hub.
Have some respect for your rotors
The process works like this: the moment you depress the brake pedal, this causes the master cylinder to push fluid through your brake lines, which in turn engage the calipers (the clamping devices that move the pads in and out). The calipers are always hooked up to the top of the rotor, as this is where contact is made with the pads. Needless to say, these thick metal discs have a very important role, and need to be checked on a regular basis for safety’s sake. Rotor maintenance is a crucial part of every braking system; it is a good idea to inspect them at least once a month.
Brake rotors are designed in such a way that the heat generated by the friction from pad contact does not reach excessively high levels, but wear and tear on the rotor surface does occur naturally over time. Major problems start to develop when brake pad maintenance is neglected, namely when the pads are left on beyond the recommended point of replacement.
Pads that reach ¼” thickness can cause grooves to appear in the rotor, and these become more prominent the thinner the pads become. This is why brake pads are equipped with metal shims; if you hear the telltale screeching sound, you know it is time to buy a new set of pads.
Rotors that have not been worn down too far can be salvaged by a process called resurfacing. This basically grinds and polishes the surface to remove the grooves, and is cheaper than having to buy a new set. Warpage can be easily detected by doing a simple stopping test. Hard brake from 30 and 60 miles per hour respectively; if your vehicle shakes and shutters excessively, this is a strong indicator that its rotors are warped.