Done this 3 times in the past 6 months. Reach in there and pull out the end of that return line(while connected to the sender) first. Don't be afraid to bend at will. As you rotate the sender the whole line will pop out through the access hole. If I remeber correctly you will need to rotate the sender about 90 degrees counter clockwise to angle the float and level sender mechanism(rectangular thing on tube of assembly) out of the tank. Not too hard, just be patient and persistent. Oh! make sure that you don't lose the screen in the tank. The old ones are bigger, very stiff and sometimes brittle. New ones fall off easily if they are not absolutely on all the way.

I used a tiny bit of silicone on the rubber gasket so that it did not deform as the sender rotated while tightening.

My problem was a rusted fuel return line under the car that broke open when trying to undo the flare nut on the coupling. The flare nuts on both of my 240s were rusted onto the return line and would not turn without turning the line with it. GRRR!

So as far as I'm concerned you're in the clear!!

Good Luck
Marty