Fuel sender repair

Just ordered a sending unit, is there a way to fix this thing reading 1/4 tank problem before I put it in? I mean like will it hold if I go through all the trouble of soldering everything the way it is specified in the how to post?
The sender wire runs to the driver side kick panel connector so check that connector. The instrument panel voltage regulator also powers the fuel and temperature gauge. I also solder the stud to the brass bar.