What are calipers and what do they do?
There are several things called calipers. One is a tool for measuring things: http://en.wikipedia.org/wiki/Calipers Another is part of disc brakes. The calipers squeeze the discs to provide retarding torque. http://en.wikipedia.org/wiki/Brake_calip…
If your referring to the calipers in your brake system, then this what they are. There is a disc called a rotor that is attached to, and spin with the tire. the caliper goes over the top half of the rotor with a pad on each side. when you apply the brakes, hydraulic fluid goes into the caliper forcing the the pads within the caliper to squeeze the rotor and cause friction, hense forth slowing or stopping the vehicle. There are also measuring devises called calipers.