1967 Park Lane Bench Seat Removal Problem
 

This is my first post. I can't find an answer to my question anywhere, so here it goes. I have a 1967 Mercury Park Lane I'm working on restoring. Issues abound, but the one I'm dealing with now concerns removing the front and rear bench seats so I can begin working on the interior. Now, the rear bench is easily removed (just push against the bottom of the seat to unhook the seat from the clips). But the front bench seat I cannot figure out. The threaded bolts that pass up through the floor and through the seat brackets are secured with 4-sided nuts. However, the nuts don't seem to turn, and all the nuts are positioned the same (symmetric position that doesn't appear to have been tightened that way) and they look like they are part of the seat bracket. So, I felt underneath the car, and there is a hole where the threaded bolt passes up through the floor, but I don't feel a nut, just an unthreaded portion that feels like a metal boot that stops the bolt from completely passing through the hole. Anyway, I tried to turn the four-sided nut, and it won't move. Also, there is so little room between the nut and seat bracket that it just seems like it wouldn't have been attached this way. Sorry for the long post, but I'm stumped. Any help would be great.