leaking fuel sending unit

Thanks again all for your input. I noticed that no only was the replacement seal thinner, but the lock ring is total junk on the new unit. I know they say not to use the old lock ring, but I was stoked to find out that the mechanic left the old ring in a box, so I reused it. Much stronger, thicker and could feel the seal as it locked into place. I did use a small bead of Permatex RTV, figured it couldn't hurt. I'm going to fill her back up tonight and see what happens in the morning and get back! CHEERS!