Fuel Valve Leak Around Threads
 

Hello,
I have a 1930 Tudor and i decided to replace the fuel valve because it was leaking a little and the inside of the car smelled like gasoline. I replaced the valve with a nice new one. The problem I have is that I tightened it as tight as I thought it should go....I did not want to split the fitting on the tank....and here is my problem....it leaks around the threads. If it wasn't gasoline I would just use pipe tape, but I heard that would quickly deteriorate.
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Is there any type of pipe thread sealing product that can be used with gasoline?
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Thanks...

Re: Fuel Valve Leak Around Threads
 

I've use Gasoila pipe thread sealant with good results. A 2 oz tube will last you a long time. https://www.amazon.com/Gasoila-Soft-...xpY2s9dHJ1ZQ==

There are also pipe sealant tapes specifically for gasoline but I have not tried them. Don't use the common white tape.

Re: Fuel Valve Leak Around Threads
 

Over the years I have used this many many times and it is great stuff.

https://www.permatex.com/products/th...hread-sealant/

Re: Fuel Valve Leak Around Threads
 

I have had good luck with the yellow teflon tape.

John

Re: Fuel Valve Leak Around Threads
 

This is the best IMO !

Re: Fuel Valve Leak Around Threads
 

I see yellow Teflon tape for sale, and other colors and types also.

Some say the product is for "Gas", but it doesn't say what type of gas. Gasoline? Natural gas? Seems odd that they don't say. Not that I can find anyway.

A "gas" is a state of form in physics, not a chemical or material makeup.

Has anyone seen a Teflon tape say that actually says its gasoline and ethanol proof? In fact, I cant find ANY products that actually say they are gasoline and ethanol proof. Some say 'resistant", but not "proof".

.

Re: Fuel Valve Leak Around Threads
 

I use a product called fuel lube for gasoline applications on my airplane.

Jim

Re: Fuel Valve Leak Around Threads
 

Unfortunately in this world as it is today I don't think you will find anything that claims an absolute in writing due to the fact that they may be sued if it leaks... just my opinion. If they say "resistant" the have a way out.

Re: Fuel Valve Leak Around Threads
 

https://www.amazon.com/Gasoila-Yello...48VD4W1NVPHMQ3

Says "for gasoline" on the reel.

Re: Fuel Valve Leak Around Threads
 

No it says "for gas". The could mean propane, butane, etc. It does state for "handling gasoline", whatever that means.

Re: Fuel Valve Leak Around Threads
 

Yes, you are right, it does say for "handling gasoline". Small print on the bottom.

Re: Fuel Valve Leak Around Threads
 

Good point.

Re: Fuel Valve Leak Around Threads
 

Jim-

That products' Technical Data Sheet says that it passes the requirements of FTM-5414 (in gasoline, and in ethanol & water, 50/50). I have not read that spec in detail.

Results indicate there was no visual deterioration for this product in gasoline, or in ethanol/water. The "pass/fail" results are for visual inspections only.

Also, there was no test for a gasoline/ethanol combination, probably because Av-Gas doesn't contain ethanol (I hope that's still true!). We don't want our airplanes rotting or falling to pieces. I guess the government considers it okay for our cars though :rolleyes:

During my New Fuel Shut Off Valve development project, I've been doing some research on a few viscous sealants. All that I've tested so far were applied onto some cleaned metal surfaces (no assembly), air cured for a day, then soaked in automotive gasoline. All the sealants just dissolved.

If I was your A&P, I would encourage you to keep an eye on those fuel seals periodically. As a good pilot, I know you would do that anyway as part of your pre-flight.

.

Re: Fuel Valve Leak Around Threads
 

I don't even know anybody who uses Ethanol laced fuel in their car - modern or vintage. I certainly don't but I find a dab of Permatex #3 works well. You'd have to try it with E fuel.

Re: Fuel Valve Leak Around Threads
 

I use Indian shellac NAPA has

Re: Fuel Valve Leak Around Threads
 

Almost all automotive fuels in the USA are 10% ethanol. There is no choice, unless you buy expensive Av-Gas or racing fuels.

So, in order to assure that fuel connections don't leak, we in the USA must contend with the devils' spit (ethanol).

Normally at this point I would start a rant. :eek::mad::rolleyes::mad::eek:

.

Re: Fuel Valve Leak Around Threads
 

Oddly, in our area, Walmart (of all places) sells ethanol free gasoline. Murphy is the brand name. It was a pleasant surprise to find it.


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Re: Fuel Valve Leak Around Threads
 

I just bought a 'non-setting heavy duty paste with PTFE' which says it is good for taper pipe threads and petrol ( that's gasoline to you). Slic-tite, made by La-Co of Elk Grove IL. It will be several months before my car is finished ready to drive so I won't be able to report if it works for some while.

Re: Fuel Valve Leak Around Threads
 

I found the repop filters and maybe repop valves are slightly off where the flare goes. Ended up using red silicone sealer and it worked, went around the threads and inside lip of the flare.

Re: Fuel Valve Leak Around Threads
 

It will work for a while but silicone is not petrol (gas) proof. It will fail.