fuel tank leak
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dominicelliott
- Posts: 1
- Joined: Mon Mar 11, 2024 2:50 am
fuel tank leak
Hi I have a new issue. I found a fuel leak on a 1/8" NPT fitting on the side above the fuel tank level probe. I tried removing and replacing plug with several different fuel sealants. So I think its coming from the brass insert itself. Thinking of trying to get a vaccume pump and see if I can get it to suck in some epoxy around the fitting. Has anyone else had this issue, and what was done to fix? All ideas appreciated. The tank is installed. Thank you all!
Re: fuel tank leak
Can you provide a picture? Mke and Model of airplane? Applying vacuum to the tank may create more problems than solve.
'53 B-model N146YS SN:25713
50th Anniversary of Flight Model. Winner-Best Original 170B, 100th Anniversary of Flight Convention.
An originality nut (mostly) for the right reasons.
50th Anniversary of Flight Model. Winner-Best Original 170B, 100th Anniversary of Flight Convention.
An originality nut (mostly) for the right reasons.
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Bruce Fenstermacher
- Posts: 10318
- Joined: Tue Apr 23, 2002 11:24 am
Re: fuel tank leak
Once you attempt a chemical fix ie epoxy, and should you be successful actually getting the chemical to be sucked into the crack, you have pretty much spoiled any attempt any one would make to fix by welding because the crack would be contaminated in a way no one could clean out.
Lots of times an attempt at the easiest repair has consequences. It takes time to go get the correct wrench but we still use a pliers and round off the nut and mess up the finish.
Once the source of the leak is confirmed, I'd remove the tank and have it repaired by a proper weld. I'd also look at the used market for a suitable tank. They are out there. I have access to 3 of them which might fit the bill if you have an A or B model.
Lots of times an attempt at the easiest repair has consequences. It takes time to go get the correct wrench but we still use a pliers and round off the nut and mess up the finish.
Once the source of the leak is confirmed, I'd remove the tank and have it repaired by a proper weld. I'd also look at the used market for a suitable tank. They are out there. I have access to 3 of them which might fit the bill if you have an A or B model.
CAUTION - My forum posts may be worth what you paid for them!
Bruce Fenstermacher, Past President, TIC170A
Email: brucefenster at gmail.com
Bruce Fenstermacher, Past President, TIC170A
Email: brucefenster at gmail.com
Re: fuel tank leak
Vacuum strong enough to pull epoxy into a crack will easily crush the fuel tank. Blocked vents have been known to crush fuel tanks.
I dont remember the dimensions of the 170 tanks off the top of my head, so a here's first approximation
21 gallon volume X 231 cubic inches per gallon = 4850 cubic inches. assume its a rectangular block.
guessing 6 inches deep. so 4850/6 = 800 square inches for top or bottom surface.
so a 2 psi differential puts a 1600 pound (evenly distributed) load on the top and bottom surfaces of the tank.
The fuel, by contrast, weighs 6 pound per gallon, so 120 pounds of fuel distributed over 800 square inches is 0.15 psi.
Be careful with air pressure or vacuum in thin-walled vessels.
Cheers,
Pete
I dont remember the dimensions of the 170 tanks off the top of my head, so a here's first approximation
21 gallon volume X 231 cubic inches per gallon = 4850 cubic inches. assume its a rectangular block.
guessing 6 inches deep. so 4850/6 = 800 square inches for top or bottom surface.
so a 2 psi differential puts a 1600 pound (evenly distributed) load on the top and bottom surfaces of the tank.
The fuel, by contrast, weighs 6 pound per gallon, so 120 pounds of fuel distributed over 800 square inches is 0.15 psi.
Be careful with air pressure or vacuum in thin-walled vessels.
Cheers,
Pete