Seat problem in John Deere 120

My 1999-2000 JD 120 has a pretty common seat. I'm not sure if the weight adjuster is mechanical or air, because it doesn't work (my guess would be mechanical). The main problem I'm having is that there's a fair amount of front to back slop in the seat. I'd say about 1/2 to 3/4 inch of travel, just enough to drive me nuts when trying to get something done. My question: Is there a way to fix this issue without tearing the seat apart? Also is the weight adjustment fixable? Machine has 9700 hours, well maintained.



Thanks!