[TRE Cup]

A sender in the 911,912,914 is constructed of a hollow tube that acts as protection and a guide for the float located inside of it. There are two very fine copper wires that extend from two different connections at the top and bottom of the tube.
The float makes the connection between the two wires. As it floats up and down , the electrical resistance changes. These changes are transmitted to the dash guage, to give you the level in the tank

So , what goes wrong:
1) The float gets worn out and some gas gets inside of it
2) The outer tube is compromised from compression < look for a dented gas tank near the driver side part of the tank
3) The glue/ crimping of the tube components fails allowing the tube to float free < this restricts movement of the float along the copper wires
4) The copper wires fail < does not sound that this is your case, as the fuel guage would not be accurate at all if a wire comes loose

Practicality of repair:
IF you can remove the outer aluminum tube intact with no dents< Remember the float needs a smooth bore to move up and down. THEN you are confronted with really thin wires for the float to rub against. You would have to source this wire, then figure out how to reconnect them at the correct length.
And again, is the float in good condition? If not, you won't find this unless you pick up a bunch of other broken senders.
So can you fix it yourself? Sure, given enough patience, steady hands, and available parts

URO recently sent us their aftermarket sender , to test, and it works like a champ, looks right too. I believe our host sells them now