Hi guys - thanks for the quick response.
So here is the deal, when I got the car I only drove it around the neighborhood but at that point it wasn't pulling and brakes seems weak, but OK. I flushed the fluid, replaced the master cylinder, replaced the brake lines with new rubber ones and then she sat while I rebuild the front suspension. Fast forward 6 months to last night...
I finished the suspension rebuild and then installed new front disc pads and stainless steel front brake lines. That point the wheel first had a lot of drag.
The system does have fluid going through it properly, and I was able to start bleeding the brakes. The wheel spins freely now with just a slight amount of drag - equal to the other side.
I ended up pulling the pads back out and carefully pushing the piston back in and it seems to pop loose at that point. I haven't had a chance yet to finish bleeding the system yet so I don't know if the piston is toast or if it was just hung up. It may well have been frozen long before I got it since I never really got hard enough on the brakes to know if it was working properly.