Thing has stripped threads and leaks. Any fixes that dont involve taking the tank out? Weve discussed helicoil (yuck). Is that legal?
Citabria fuel drain valve
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James331
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James331
Wing tanks or the bottom tank?
Dan Thomas
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Helicoils don't seal all that well. You'd have to Loctite it in or use Teflon sealant (NOT Teflon tape). But I think it would be legal. Helicoils are commonly used in some aviation applications. Your bigger problem might be insufficient wall thickness remaining in the boss to use it.
tyndall
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LawnDart
If you have the room, drill and tap the next size bigger then bush it back down to standard. Otherwise, helicoils aren't great but they do work. If they seal on a carb at 5-6 psi they will seal on the bottom of a tank. A time-sert would be a bit better though.
Jimmy cooper
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Too important to shade tree it. I'd remove it regardless where it is and have it repaired correctly. A wing tank is not that tough to get to and remove in a fabric aircraft.
You're going to have to cut the fabric off the tank area to do it on a Citabria. I'm guessing that's what the guy wants to avoid.
Are the threads actually stripped or did the drain get overtorqued and split the bung? A helicoil might be a reasonable repair but I'd guess the tank will be coming out at some point to fix it.
Jimmy cooper
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What he wants to avoid is the tank leaking into the wing and then into the cabin if it's a wing tank. Can be a very serious problem. For someone with fabric experience its a breeze.
Dan Thomas
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Drain valves ar NPT, how do you strip pipe threads?
Crossthreading, or someone tried to stick a 3/8"-24 threaded valve in it.
Dan Thomas
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For someone with fabric experience it's still a pile of work. I've done plenty of fabric, and have taken the tank out of a Citabria that I had previously recovered. Reinstalling the old fabric (if it was cut back and one edge left attached) presents a huge problem in getting it tight again. Installing new fabric requires considerable overlap to get the requisite adhesion, and a bunch of tapes and the fastening rivets, and then all the various coats to get it back to where it was. It's no small matter. The tank repair would be a piece of cake compared to the fabric repair. Masking the whole thing to control overspray and all that.
Jimmy cooper
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It all depends on ones background and experience. I watched a pro take a tank out of a t craft that leaked and ruined the headliner, etc. For him it was a walk in the park . He replaced the old fabric and you could not tell he'd been there. If your a novice, like me,its daunting.