Installing Kelsey Hayes Caliper Pistons ?

I'm finally started to reassemble my 4 piston Kelsey Hayes calipers. I'm going to using DOT 5 in the system so I'm also using the same to lube the piston seals and outside walls of the pistons. I installed the new seals in the bores, but I'm having a lot of trouble installing the new pistons. They seem to be too tight. It took everything I had to push the pistons in. Now I can't even pull them out with my fingers. This just does not seem right as I'm figuring that the darn things are going to end up hanging up on me when installed. Any opinions on this??