Well my calipers were just rebuilt recently and all the seals look great but when I was replacing the pads the other day i made the mistake of allowing one of the pistons come out of the bore. I tried to just push it back in but tore the one lip seal. So I went out and bought a rebuild kit and figured I would just replace the one since the others were new and that way I would have a second try at things if it leaked again..  Well needless to say i put the new seals on it tried to push it in again and it leaked the bored looks absolutly perfect so what am I doing wrong here beside everything? 75 L-82 Vette

Iffin it were this old dude, I would open the bleeder valve and push the cylinder into the bore making sure the lip of the piston seal is facing inward. put your outer dust seal on and bleed.

I'm guessing the lip of the piston seal rolled up on you when you reinserted the piston.

 I'll  second that

Make sure you have the seal on the correct way, to start with. I know it may sound silly, and I mean no disrespect, but you'd be surprised at how many folks don't pay attention, or just don't know which way a seal faces, in relation to fluid pressure. The lip of the seal should face to the inside of the caliper bore.

The spring behind the piston tends to make installing the piston/seal a bit tedious, but it can be done. If you have a set of feeler gauges, select a small one, maybe .015", and use that as a seal installer. Use the feeler gauge to coax the edge of the seal down into the bore. Just slide the gauge around the outside of the seal between it and the edge of the bore, while pressing in lightly on the piston. Sometimes turning the piston at a slight angle to the bore will help get the seal started into the bore.

Also, another issue with the '65'82 Corvette brakes has to do with corrosion of the pistons themselves. They can become so corroded that they will spring a leak in the piston somewhere. Check yours carefully. I've got a set I took out of some calipers that wouldn't hold any pressure due to severe corrosion.

hth

I found this link looking through an old sharkbyte issue gives step by step instructions it even has photos for those of us who scratch there heads when bombarded with tech info. Hope it helps