They are great old tractors. If you can get a reproduction owners manual. As for the seat. It's most likely just a bushing king and suspension spring. Both are very common to wear out. The front wheel seal initially used gear oil. I just put grease in mine and called it good and so far has not been an issue. Make sure the throttle linkage and governor linkage operates smoothly. As it starts to wear out it has a tendency to occasionally want to bind. The other is the PTO. Underneath there is a access plate to adjust the PTO clutch. Open and inspect. If there's some oil on the inside of the access plate go and spray the PTO clutch disc with some brake cleaner to help prevent slippage.
They are great old tractors. If you like the Ford 8n size platform the Super 55 is all that with about 8 more HP and an independent PTO. I use the heck out of my 55 doing farm chores like hay work and spreading manure.