As you can see in the photo (which is side ways unfortunately) in the link in the first post, it looks like it is leaking from the center not from the spin welded flange. Here is a link to a picture of the spin weld sensor that is used:
It doesn't need a grommet because the screw doesn't protrude into the tank. In other words, even with the screw removed it should not leak. Am I right?
I think the spin weld sensor is leaking between the metal probe sensor and the plastic weld flange? I think when I try to tighten or loosen the the screw the metal probe sensor is twisting as well?
Do you think LeakSeal flexible rubber coating would stop the leak if I sprayed it on the screw and probe in the middle of the spin weld sensor? , has anybody ever used it?