The bolts holding the seat in place sometimes have locktite on them. Crawl under and find the nuts that the bolts thread into. Apply some heat, as in propane or map torch. You don't have to get the red, but do have someone inside to make sure things don't start smoking or catch fire. I would used impact socket, tork socket to break them loose. Shouldn't take more than 500 degrees F if I recall correctly.