There are also several important considerations to make when choosing brake calipers. "Caliper selection is based on two main criteria," Bush says. "One is the required pad volume, and the other is matching the piston area to both the master cylinder volume or pressure output and the overall bias requirement. Heavier, faster cars running longer races in sustained heat will wear pads far more quickly than a light car running short sprints on a light-breaking track. The pad wear rate dictates pad size requirements and therefore the overall caliper body size. But it's the actual piston area size that must be considered when trying to set up bias or affect clamping power. Going to a larger-caliper body doesn't necessarily give you more stopping power unless it also has increased piston area or is capable of effectively running at higher line pressures. But, it will certainly take longer to wear through the larger pad."
Caliper MaintenanceYou religiously bleed your brakes and even flush the fluid at scheduled intervals. You keep a sharp eye on your rotors for cracks or signs of warping. Pads are properly bedded. Lines are checked for leaks. You've got it all covered, right? But how often do you rebuild your calipers? Do you even have a caliper maintenance program? If not, you need one. Carl Bush of Wilwood Engineering has specific tips for keeping your calipers in prime condition:
"A good way to judge caliper maintenance intervals is based on pad wear. After a caliper has been used long enough to wear through a set of pads, some basic routine maintenance should be performed. Please note that it's not necessary and usually not recommended that the caliper halves be separated during a rebuild. As the pads wear, the pistons become extended from the bores.
"Before reseating the pistons into the bores to accommodate the installation of the new pad set, the pistons should be removed from the body, fully cleaned, and inspected for wear. Never use anything coarser than fine steel wool to clean the pistons. The pistons should be clean and completely smooth on the outer surfaces. They should slide freely in and out of the caliper bores when the seals are not present. Damaged or worn pistons should be replaced. New O-ring bore seals should be installed and the pistons then fully seated into the caliper body. The caliper should also be cleaned inside and out and blown completely dry before reinstalling them on the car.
"This is also the time to completely flush the system with fresh fluid. Any brake maintenance should also include a routine inspection of the entire caliper body, including the areas around the mounting lugs, the bridges or bridge plates, bleed screws, and fluid tubes-if so equipped. Worn, damaged, or suspect parts should be replaced. The system should also be flushed and the calipers equipped with new seals at the beginning of each new season. If a person does not possess the equipment or knowledge to confidently and correctly carry out the maintenance procedures, they should seek the assistance of an experienced and capable technician."