My seat was beat and I needed some additional suspension so I bought a seat and suspension from K&M Manufacturing
KM 406 Uni Pro – Grey Viny $159, ultra-low mechanical suspension #6081 $158, slide rails # 6043 and retractable seat belt $29
A brief post at http://www.tractorbynet.com/forums/power-trac/99648-replaced-seat-pt-1850-a.html
The seat suspension is wider than the PT mounting plate so I made an adapter plate shown below:
Here is a picture of the adapter plate mounted on the slides:
Here is the suspension mounted to the seat frame:
When mounting, I had to add a few washers for clearance:
Here are pictures of the seat after installation:
