brass gas tank sending unit float resolder?

Can the gas tank sending unit brass float be resoldered? I have one with gas inside. If I drain and flush out can it be repaired? If so what type of solder?

Yes it can, but most likely not worth the effort.
I had same issue and found that once it's bad enough to hold gas there's just too many holes to solder. I used normal a Radio Shack solder used for electronics.
New float is only $6-$8

Ford part number coaz-9202-b $10 on amazon

Just replace it with the plastic one and forget-about-it..
https://www.ebay.com/itm/Fuel-Sender-Flo...m4383.l4275.c10

years ago i went to the hardware store and bought a tapered cork like would go into a old type thermos bottle,worked great!

^^^ that's unique! it still read the same?

I agree use the Ford one.It will out last the car.i saved a bunch when I was working and replaced the senders in them.Works better than any others.Rocky