Hello,
The enclosed files show the internal mechanism of your sending unit and some other system info.
I took mine apart and cleaned it and it worked again. You can pry the top off to get to the internal mechanism, clean the contacts, etc. Also, check the bulb to see it is not leaking and full of fuel. If so, you can probably buy one of those or have it evacuated and soldered. A cork float may also be substituted if you can't find one made of brass. The King-Seeley writeup says they can't be repaired, but I think they were wrong. Keep searching and send me an email if you wish more info.
Jerry