Caliper overhaul includes replacing the dust and piston seals, and therefore requires complete disassembly. Don't panic; it's easy. Still, it's worth stopping by your dealer well in advance to purchase the seals, and be sure to ask how many sets you'll need for each caliper. Some manufacturers sell kits that include parts for the piston pairs on each side of the caliper, while others sell them individually by piston. If you're lucky, the dealer will have 'em in stock.