This might be very helpful , i think there is also a diaphragm on the back side of the speedometer too.

I think Ii will be in need for gaskets, or seals, for both.

So please distribute if you can get the part numbers.

My Chevy Viking 1959

Ulf Hedlund. Eskilstuna. Sweden
[email protected]
Also:
Ford Galaxie 4 dr 1959
Ford Custom 4 dr 1964
Ford Mustang GT 2005