I rub a little bit of brake fluid on the O-ring to help it slide into the bore. It's pretty hard to get it started, and you have to start the piston dead straight or you'll ruin the O-ring. I also place the dust boot on the piston before I press it in. Installing that afterwards is damn near impossible. After the piston is in place, then you can carefully tap the dust boot into the caliper housing. /forums/images/graemlins/thumb.gif
There's one O-ring that doesn't come in the rebuild kits. Inside the main piston is a second piston, which is part of the e-brake mechanism. It's a royal pain-in-the-a$$ to get it apart, plus it's spring loaded, so I guess that they don't consider that a user-replaceable part. /forums/images/graemlins/frown.gif There's an O-ring between the two pistons, and if it's leaking, then brake fluid will weep from that little hole in the face of the main piston. /forums/images/graemlins/eek.gif At that point you pretty much have to pony up for a rebuilt caliper. /forums/images/graemlins/angryfire.gif
