I finally figured out how to remove the seat on my 45-40. It is quite simple once you see how to do it. There are just 4 bolts holding it in, that and gravity. The assembly must weight 75 pounds. It took two people to pick it up and move it off the tractor, and put it back.ł
The four bolts are located at the front and back of the seat mount assembly. The ones at the front are obvious. They bolt two arms down to the tractor itself. The rear two are a little more complicated. They are at the back of the seat and can be seen by moving the seat all the way forward. They are located in two recesses in the seat mounting plates. The problem is that they are also located behind a cross member for the seat assembly.
Remove the three retainers on the rubber boot.
Slide the seat all the way forward.
Move the seat back about an inch and a half.
This should give you room for a socket to reach over the cross member and remove the bolts.
If you remove the rear bolts and loosen the front bolts, the seat will tilt up. The only problem is that the seat is so heavy it is very difficult move into the tilted position. Putting the seat in the tilted position would be something you might do when you are shutting down for the day, but not something you would do when you got off the tractor for only a minute or two.
Something else I noticed while working on the seat, all,of the parts of the seat and everything else on the tractor looks like it was cut out with an ax. Everything is very crudely made. Also, the welding looks like a Mud Dobber did it. I don't know, but all this does not inspire much confidence in the overall tractor. Perhaps I screwed up in this purchase.