You should place your query in the Parts Wanted section. Someone may have some to sell, and maybe even nearby!
As for the pistons for the wheel cylinders, I believe you can find complete rebuild kits that include the spring, pistons, and cups.
I loved looking through my old farm truck when I bought it. Still get a kick out of some of the things I found. For example, I found an old Hires Root Beer bottle opener in the ash tray. That's a keeper! I also found old beat up license plates were used to plug holes in the wood flat bed it had. Out of state and rusted through. Too bad.
