Gas tank leak

One trick I have heard is to stack two rubber gaskets, but I would try bending the ears first. I agree w/ ESP47 that the lock ring tabs should sit in the slots on the tank ring. I know that tends to make the ring lose, so tempting to leave the ring at its tightest, but it could then vibrate lose.

As cudamark mentions, a younger brother had a Duster where the tank rusted thru on top after spilling water in the trunk. There is a recess in the tank under the large round plastic body plug in the spare tire well, a great place to hold water. That was in Florida where spills don't evaporate. He and Pa insisted on a $1 epoxy fix, though I advised getting another tank. Didn't work so my brother sold the car cheap ~1983. Nice looking car - yellow w/ black race stripe, though a slant six w/ 3-sp manual ('72 I recall).

I didn't bother replacing the factory blanket on top of the tank in my '65 Dart recently. Couldn't find it and vaguely recall discarding since degraded. I glued leftover trunk weather-stripping in a few bands as cushioning. It feels firm and quiet. I recalled my brother's experience and thought better to have air gaps so water can't sit on the tank. I also wire-brushed and painted the outside. The inside looked pristine. Hold it so sun shines in the filler hole and you can see well.