Fuel sender unit.

(1957 DS19)

The original fuel sender was so corroded that the floater disappeared and the arm was reduced to a thin wire.	Even the rubber membrane was melted.
Believe it or not, I kept the coil as a spare part.	I found a good 6V sender. To put it back in good working condition, the 2 brushes on either side of the coil (red arrows) need to be sanded (600 grid) as well as both sides of the coil. On many senders, the rivet holding the male connector does not provide a good electrical connection; I have soldered the rivet, washer and plate together (yellow arrow).
I used a tank lining (or coating) product to protect the floater and the arm.	Installed and working like a charm.