Not difficult to fabricate a new shaft and the washers on a lathe.
Not difficult to spread the end of a new shaft to expand over the lower washer.
Not difficult to have a new steam die fabricated to mold the molded (not flat) diaphragm, but you can easily buy a new (2022) loaded truck for the cost.
We have had a couple of customers try using flat diaphragms with zero success (insufficient movement of the diaphragm).
If you really want to try this, a good friend in the fuel pump kit business has suggested fiberglass-reinforced Buna N for FLAT diaphragms to be used with ethanol.
The better solution (opinion) is to start the engine every few days to assure the fuel does not totally evaporate from the carburetor (besides, more fun than just watching it sit unattended
)
Jon
