You're talking about the o-rings on the caliper piston, correct?
Its been a while since ive messed with them, but after you get the new o-rings on, put some grease around the ring to help slide the piston back in. You may be able to use a c-clamp to push it back in, or use a socket inside the piston and use a vise to push it in, etc.
'06 Raptor 700-Sikk front bumper, rear grab bar, pro armor shifter, Dr. D reverse setup
'04 660 - Sold