Drilled hole too large for vent line bulkhead ell in tank rib

I read 9/16 where it actually said 7/16 when drilling the hole in the inboard tank rib for the AN833-4D bulkhead ell. The oversized hole is big enough for the ell to slip through the hole entirely.

My intuition is to proseal and rivet a ~two inch round patch over the hole on the inside of the tank then drill the center of the patch to the proper size, but I'd appreciate confirmation that this is the appropriate course of action.

I could also just patch the oversized hole and relocate the vent line, but I don't know what consequences that will have later in the project. (This is a 7A; the plans say "locate approximately" when discussing the hole in the first place.)

Thank you for your help

Vent

Why not replace the rib? A patch would work but you could also use an appropriate size fitting with reducers. I would replace the rib while access is easy.
Tip
When you locate the vent hole, give a close look at how you're going to set the skin to rib rivets right next to the fitting or put the fitting in after setting those rivets.

wirejock said:

Why not replace the rib? A patch would work but you could also use an appropriate size fitting with reducers. I would replace the rib while access is easy.

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I would if it wasn't riveted and prosealed to the tank skin already. Installing this fitting was basically the last thing before riveting the baffle and closing up the tank.

Thanks for the advice.

Advise

ToadMan8 said:

I would if it wasn't riveted and prosealed to the tank skin already. Installing this fitting was basically the last thing before riveting the baffle and closing up the tank.

Thanks for the advice.

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Ooops. My advise is not much use then. Hopefully one of the gurus will answer.

A simple fix is to use two aluminum AN washers like Van's sells AN SPACER, 4D

Put one on each side of the bulkhead using pro seal. The AN fitting will hold it all together.

Carl

If you know someone with a lathe it is easy to machine a shouldered washer to fit the larger hole.

Stewart Willoughby
6, FWF.

As long as you take proper steps to seal the attach rivets and 2" round plate, it would be a totally acceptable repair.