2012 Sportsman 400/500 and EFI Tractor Service Manual 9923412, Page 344Get this manual
BRAKES 7Measure the thickness of the pad materialReplace pads if worn beyond the service limit
Assembly
1Lubricate mounting bracket pins with light film of disc brake caliper lube, and install rubber dust boots
2Compress mounting bracket and make sure dust boots are fully seatedInstall pads with friction material facing each other