Author Topic: 40 gallon in bed pickup truck fuel tank leaking at fitting  (Read 1508 times)

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Offline Busted_Knuckles

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40 gallon in bed pickup truck fuel tank leaking at fitting
« on: June 22, 2012, 02:37:44 PM »
Ive got a 3/8s wall rectangular fuel tank, its a home grown tomato. For whatever reason, who ever built it decided that pulling the fuel from the side, almost at the bottom was a good idea, instead of the top, like most fuel tanks.

So Ive had it for several years (it was several years old before I bought it), I keep 40 gallons gas in it for all the small gas units on the property. Anyhow, last fall it started to weep, at the threaded elbow that goes into the tank.

All they did was thread the 3/8s wall of the tank and threaded a brass elbow into it. Well now it leaks, so I took it apart to re-seal. Question is, what to re-seal it with, for the threads are 100% of the time with fuel pressure (static load from weight/gravity) against it. It appears to have not been sealed, there is nothing on the threads of either side.

What should I put on the threads to prevent it from leaking again, any suggestions ? Not sure if Teflon tape will do gas long term, or if I should JB weld the threads and make a permanent install, and hope not to strike and "crack" or break the elbow in the further.

Suggestions ?
« Last Edit: June 22, 2012, 03:57:56 PM by Busted_Knuckles »

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40 gallon in bed pickup truck fuel tank leaking at fitting
« on: June 22, 2012, 02:37:44 PM »

Offline Thefalconman

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Re: 40 gallon in bed pickup truck fuel tank leaking at fitting
« Reply #1 on: June 22, 2012, 02:47:32 PM »
I would clean it up real good and use the JB weld .

Offline 70redbee

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Re: 40 gallon in bed pickup truck fuel tank leaking at fitting
« Reply #2 on: June 22, 2012, 03:37:21 PM »
I would make a permanent seal for the bottom. Close it off permantely and move it to the top. You could get a galvenized fitting which seals from the inside as well as the outside to close it off. Then cut the hole in the top to move the pump. Empty the tank before doing any of this and fill it with water in case there might be a spark from the drill or saw when cutting.

Offline rusty

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Re: 40 gallon in bed pickup truck fuel tank leaking at fitting
« Reply #3 on: July 11, 2012, 12:23:20 PM »
Kind of sounds like it was designed as an gravity feed set up to begin with.

You might consider Loctite http://www.summitracing.com/parts/LCT-37615/ I've used it in similar circumstances with good results.
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Offline Busted_Knuckles

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Re: 40 gallon in bed pickup truck fuel tank leaking at fitting
« Reply #4 on: July 24, 2012, 05:06:56 PM »
Not having the time or want to modify it, I too it apart and put avitaion gasket sealer on all the NPT fittings. I found when disassembled, that is had been sealed with white Teflon tape. I called my buddy that I got it from, and asked when it was put together, he said about 16 years ago. It was "sweating" fuel, so the Teflon tape didn't do to bad, being that its not to be used in that application.

I looked for Loctite has a sealant for petros (the stick Rusty posted), but my local farm store does not carry it, so I went aviation sealer. I had some avaiation sealer, but its 20+ years old, and it turned hard from lack of use.