As Johnny mentioned sometimes it's quite difficult to get the piston in all the way as basically a ridge of corrosion and brake dust and other goodies build up on the pistons. I avoid pushing the piston in all the way if it's possible (not always possible) because of this. There are stories of this ridge of brake goodness damaging the seal. If you aren't going to remove the piston and clean, basically rebuild the caliper, then avoiding pushing all the way is best, but it will go flush on every caliper I've ever seen.
Now back to the man's problem.
I can't see anything that hasn't been covered, but I would probably disassemble everything, make sure that you do in fact have the right part number. Reassemble and see if you hadn't done something wrong. Something as simple as a twist in the line could do it. I put a caliper on in my car wrong once. Flipped it over putting a twist in the flex hose and it made the fluid returning impossible, almost as though there was a kink. Therefore the brakes were "stuck" on.
Just carefully go over everything. You may never know what went wrong.
Now back to the man's problem.
I can't see anything that hasn't been covered, but I would probably disassemble everything, make sure that you do in fact have the right part number. Reassemble and see if you hadn't done something wrong. Something as simple as a twist in the line could do it. I put a caliper on in my car wrong once. Flipped it over putting a twist in the flex hose and it made the fluid returning impossible, almost as though there was a kink. Therefore the brakes were "stuck" on.
Just carefully go over everything. You may never know what went wrong.
