I guess the rust is what I am reacting to. The bed sides are more rusted than I want to admit and the rubber washers minimize the metal to metal and further deterioration. i don't think I am creating more of a water issue, arguably adding a small 3/32" space (after the washer is compressed) might allow water to freely drain and not collect in the metal parts. The fender welt is probably the least expensive part on the truck - maybe I should just stick with that.