4 bolts and nuts wont fix that!!!!! that crack supports the entire back of the seat frame, when a track breaks like that, and you get in the car, the left side of the upper seat frame lays back almost to the rear seat, the actual seat tracks plays a large part of the whole frame of the seat, if the track breaks like that, it messes up the whole seat, it has to be welded or replaced, but welding it makes it weak, and it will break easier down the road than a track that hasnt been repaired. but no way with a few bolts fix it, not when it is all structure support where the track snapped.