I cleaned out the pocket lightly with a dremel, and that actually got the bushing to seat 3/4 of the way but not enough. I've probably removed a few thousands worth of surface rust from the back wall and I know I've gone far enough when I hit the black subframe coating. I'm doing the finish smoothing with sandpaper so I don't go too far. What a PAIN. Gonna try the other frozen mount and hope I get lucky. The other side shoudn't have this problem. I wish I would have started with that side so I know what the pocket is SUPPOSED to look like.
Figured out the rust in the pocket is due to the large rubber backed washer that was missing from the bottom of the mount...allowing water/snow/grit whatever in there.
