More on Fuel gauge sender

[Steve Sherman]

Got the gas level low enough so that I could pull the sender tonite.
 The problem was the wire to the wiper broke off, creating an open
circuit.  So I cleaned things up and soldered it back on, and gauge is
working as before.

Which leads me a couple of follow up Q's:

1. The solder job is probably temporary as the small tab on the wiper
had broken off from stress.  Before I go out to get a whole replacement
sender, I was curious if any lister might have an old not necessarily
working sender lying around with a good wiper they'd like to part with.
[Probably a long shot, but...]

2. This fuel gauge has always read high.  1/2 full reads 3/4 on the
gauge, empty reads 1/4 full.  I was wondering if that might be due to
the  Avant having the wrong sender in it, causing it to read high.  The
numbers on the sender I have are 221 824 027 (with /'s around the 027).
 Is that the right part for a 20v avant, or could someone have put a 5K
or other Audi sender in?

TIA