So, when I removed the left tank due to minor leakage on some machine screws, I decided to pro seal the access cover and the fuel level float cover. I had followed the plans years ago when I built these tanks and experimented with a popular process for the right tank, and the plan description for the left tank. The right tank held its seal. This left tank did not. So now, I am Pro sealing the left tank access covers. Many RVers like the proseal approach so that's it. The product cost about $20 and was more than enough for this job. To keep most of the proseal out of the nutplates while it was being applied, I used the old Phillips screws to block the nutplates. That worked well. It went together using recessed hex head machine screws this time. I will test the seal after it sets ups in a few days.
Test stick to see when it has set up permanently.
Ready to accept pro seal after I put machine screws in the holes to block proseal.
Completed. Also riveted the B-Nut antirotation device inside the cover plate
