I have a Moss aluminum gas tank in my car that I installed about 4 years ago, and have always smelled a little whiff of gasoline while driving. Finally, about a year ago, I pulled the forward trunk panel and discovered that there was a pretty evident gas stain around the cork gasket that seals my sending unit. Now, I sealed that gasket very well so I know this shouldn't be happening. Well, I went ahead an heavily coated the whole perimeter of the sending unit with Permatex Aviation and this stopped it. Anyway, since the gas tank is now out (didn't want to weld about gas lines for my suspension), figured this is a good time to change out the sending unit anyway; the old new unit was never accurate. Bought a new unit with new screws (6) and gasket. What do I find but two of the #10 - 32 screws were stripped in the aluminum. That is why my seal never sealed. Again, very fine thread in very soft aluminum is not a good mix. I retapped all 6 holes and went oversize to #12 - 24 thread screws and rubber sealing washers on each screw. A real PITA but gotta do it. And had to drill out my new sending unit flange to accept the new larger screw. Will place them with some sealer on the threads as well.
It never ends....
It never ends....