Piston stuck after rebuild

Hi guys, I just rebuilt my master cylinder and caliper, and upon assembly of the caliper I couldn't fit my piston in fully. It is stuck maybe 1/2-3/4" in. I assembled the rubber parts with brake fluid for lubrication. I have never rebuilt my caliper before so I'm not sure how much resistance there should be, is this typical? If so, any suggestions on how to compress it? I bought a harbor freight brake piston compressor but it does not work with this caliper due to design (http://www.harborfreight.com/disc-brake ... 68973.html). I think my c-clamp would work, but I don't want to force it if there is a problem.

 

Im actually rebuliding my calipers at the moment. The piston should push back with firm finger pressure.
Im assuming that you have the caliper off the bike and the hose is not connected?
Did you clean out both seal grooves, they need to be perfectly clean.
I think I would pop the piston back out and double check rather than force it.
A smear of red rubber grease (ok to use with brakes/fluid) in the seal grooves is also a good idea to help it resist future corrosion.
good luck.

 

Definitely don't' force it in. You may have it slightly cocked to one side. Remove the piston and carefully refit. be sure that the piston is shiny-smooth where it enters the caliper bore.