front brake locking

I'll try to make a long story short. First of all, the car is a 92 Cutlass Ciera S, 6 cylinder. This is my daughters car and the front right brake keeps locking up. Here is what I have done and noticed. Replaced Calipers, rotors and pad...still locking up. Before the next replacement here is what I noticed. While bleeding the brakes I could hear a hiss on the right brake every time I open the bleeder. I didn't hear any sound on the left brake or the rears. So now I have replaced the master cylinder and bled the everything. The strange thing is that I still hear the hiss while bleeding the right front. I can't hear it from any other brake. I have not road tested it yet but I'm beginning to think it might be a brake line. I don't see any leaks though. Anybody have a thought on this?
Note: I have eight cars between myself and my kids and have done brake jobs on all of them. This one is stumping me.
Okay...it wasn't that short, but I tried. :banghead:

It's entirely possible that you have an obstruction in that line, probably around the flex line area. While the pressure can reach the piston, it probably takes longer, therfore the pressure drop upon release would also take longer. I think that would explain the hissing noise you hear.
Anyways, I have seen debris in brake lines before, and with everything you have done so far, I'd say you should try to rule out this possibility next. Disconnect line from Master, disconnect at begining of flex line... try to blow compressed air through the line. Disconnect brake line to caliper, blow air from begining of flex line through that portion... refill, bleed, and pray to sweet baby jesus. Something tells me there is a screen in the begining portion of the flex... but I cant remember if its this model..

Welcome to AF. Replace that flex hose to the caliper, also.