2012 Sportsman 400/500 and EFI Tractor Service Manual 9923412, Page 350Get this manual
BRAKES REAR BRAKE PAD
Touring Pad Removal
1Elevate and support the rear of the ATV2Remove the rear wheel 3Loosen pad adjuster screw 2-3 turns5Push caliper piston into the caliper bore slowly using C-clamp or locking pliers with pads installed
NOTE: Brake fluid will be forced through compensating port into master cylinder fluid reservoir when piston is pushed back into caliperRemove excess fluid from reservoir as required6Push caliper mounting bracket inward and slip outer brake pad past the edge to remove4Remove the two caliper mounting bolts and lift caliper off the brake disc