2012 Sportsman 400/500 and EFI Tractor Service Manual 9923412, Page 348Get this manual
BRAKES Inspection
1Inspect caliper body for nicks, scratches or wearMeasure bore size and compare to specificationsReplace if damage is evident or if worn beyond service limit
Reassembly
1Install new caliper seals (A) in the caliper body (B)Be sure groove is clean and free of residue or brakes may drag upon assemblyC B