Time to see if all of the work has paid off. After a few false starts due to caps that weren't quite tight enough and were leaking, I got things sorted out and started the leak test on the left tank. All this involves is putting a schrader valve in the drain opening, capping the fuel pickup fitting, and putting a balloon on the vent line. It only takes 1-2 psi to do the check, so just enough to blow up the balloon a little bit is all that is needed.
One thing that Van's calls out is the need to cover the filler cap with tape, since it's not perfectly air tight. Laughably, this turned out to be the hardest part of the whole process. I tried packing tape, but no matter what I did, I couldn't keep it from leaking (sprayed it with soapy water to test).
I finally switched over to heavy duty Gorilla tape. That seems to be working, but we'll see what things look like in the morning. The only problem with the balloon test is that it'll inflate and deflate depending on temperature. I did spray the entire tank down with soapy water and didn't see any leaks beyond the filler cap, but if tomorrow the balloon is deflated and I can't tell if it's because of temperature or a leak, I may switch to using a water manometer instead. At least with that you can mark the water level at a specific temperature and then wait as long as you need to for that temperature to be hit again to recheck the level. Given what I've seen so far, I'm cautiously optimistic. I think may actually have a leak free tank.
I went ahead and got started on the ribs of the right tank. It's amazing how much faster things go the second time around. I prosealed and clecoed 3 ribs. I'll shoot the rivets tomorrow night.
