[ccjohnson]

Have no square flange on ours. Have replaced both sending units without pulling tanks. It can be done put takes patience. kind of like one of those bent nail puzzles. Be aware that the flange is 2 piece and needs to be kept as such with at least one bolt still partially screwed in so that the bottom flange doesn't fall off into tank. But if it does, it will usually hang up on float arm so you should be able to retrieve it. Bottom flange will have a "flat edge" cut off one side so it will go through hole in tank.