Yesterday I went a bought two new front rotors and some ceramic pads. I got the at a local place Robbins. I had a warped one on the pass side of my 97 leg wag. So I install, clean and grease everything put it all back together and take it for a ride. I put my summer tire back on at the same time so when I stopped to adjust the air pressure I see smoke and smell my brand new pads. I go home take it all back apart to see wtf and find that only one half of one pad is worn. So I check my single piston caliper and it's fine. I was the outer pad that was rubbing. So I reinstall and as I do I notice that when I tighten my lugs I loose the little play that I have in my wheel. Bad rotor?? What else could it be??

I had this same issue with my '95 legacy, turned out to be the caliper(s). You stated the piston on the caliper slides/moves right? On the caliper there are=a rubber boots located on the top and bottom with a cylinder that slides back and forth inside. The brake caliper bolts slide through this portion of the caliper, which should slide freely. Hope this helps. It is possible the rotors are not the correct size......food for thought.

One pad sticking and rudraggin means that either the caliper piston is stuck(which it sounds like you checked) Or the sliders are sticking.

 

Disconnect the lower caliper bolt, swing the caliper off the rotor, then slide it back off the top bolt. Slide the sleeve out of the lower caliper bolt hole, and grease it up. Grease up the the top slider and put it all back toghether.

 

The caliper must be able to "free float" on those sliders, or else one pad or the other will end up doing all the work.

It was the bottom slider. I thought for sure I checked them all. It's froze right up. I tried everything to get it free including a torch! So the search begins for a caliper support bracket. Thanks for the help!

Yeah, those things are notorious for rusting up!! Especially for us in the rust belt. I've had to take an hour per side just to work them loose before! Good luck!!!