Oops fitting, fitting?

[rwthomas1]

Hello All,
I'm struggling with the Oops fitting installation. The three in the sump have been drilled out and cleaned. The custom installation/sanding tools work great for two, but I'm having trouble with the third. The small one that faces the right side, I believe? The hole is so close to the sidewall of the sump that the sanding tool fits at a slight angle. I can't get it to cut a smooth flat seat. There is a nice thick section of plastic on the sump wall from the original fitting. I have tried every Dremel bit I have, nothing can quite get at it. Same with chisels, and a bunch of other tools I tried. Any suggestions are appreciated. Beginning to think a new tank is a better idea....
Thanks, RT

[racaldwell]

Hi RT, I had the same problem when I did mine back in the spring. My solution was not the normal way this has been done but it works. I have had avgas in the tank since and no leaks as in sits in my fuselage.

That hole ended up oval to get the fitting off the sidewall even after I sanded down that side of the fitting. I used proseal and aluminum sheet between the fitting and the tank inside surface. The fitting when tightened compresses the proseal tight to the plastic - think as a very wide washer. The aluminum sheet barely fit into the tank spout. One sheet picked up two holes and the other sheet the last hole, but it had a 90 deg leg to overlap the 1st sheet. The proseal squeezed out the openings as the fitting was tightened and the outside nut has plenty of proseal on it. Pressure tested after curing a week and that worked.

I say proseal but it is actually the new tank sealant that Van's sells now instead of proseal.

Rick Caldwell
Xenos 0057