VCCA Home Forums TECHNICAL - 1945 AND NEWER 1946-1948 Thread seal for fuel filter

how should I seal the threaded pipe coming out of the filter,not being the compression type

I put a little bit of this
Put just a little bit on the threads then tighten down.
Loctite thread sealant

Interesting it says nothing about gasoline resistance

I was always told never to use thread sealant on any brake or fuel lines. Coolant and oil fittings only. Are you worried about a leak or is it already leaking at the fuel filter? Have you tried a new brass fitting first?

Aristech's suggestion would work just fine since its resistant to solvents.

I just twist'em tight dry...If they leak, twist'em some more...It's a bit trickier between the filter and the carb, all I can say is say focused

I have not installed the unit,just don't want any gas dripping!The last filter I had used "repro unit" the gasket disolved and clogged the carb,I junked it,but it is time to get one back on.I had to make a gasket out of cork..The filter is a Durex Moraine,this is correct for the year

If its pipe thread I would use a little teflon tape.If its a compression fitting or inverted flare fitting then just tighten it up. It would really help to know what style fittings you have.

Don't even think of using teflon tape on a gas line. A few times it works but more often it produces small shards of the tape to plug or stick in passages.

I would install it, tighten it and then if it leaks worry about it later.

Likely ethanol got to the gasket in your "repro unit".

Yes I know teflon tape is bad news on gas lines

I had heard that Teflon and gasoline don't mix. But Teflon tape is the only thing that I could find that would stop the leak at the 45-deg fitting between the carb and my fuel filter. I made sure that it didn't fold it over the end of the fitting. No problems. Guess I was lucky.


- Lonnie

I hadn't seen a 45 bend used before...Rather stylish...And I can see why some Teflon tape would probably be needed...Having to stop at a desired position and all...I don't think I have the nerve to try that. Thanks for sharing...

Lonnie, I,ve used Teflon tape on many things over the years
including my gas lines. If you take your time and are careful as you stated you'll be fine.
Happy Motoring

It often can't be avoided...Just be careful...I start it several threads from the end and pull it tight...

Teflon tape is much like silicone sealers-if applied properly it will work fine. The problem begins when the user decides more is better. As Kevin stated apply a couple threads back and a single wrap is all thats needed. Its purpose is to fill the small voids in the pipe threads without having to overly torque the fitting and chance cracking the housing. Pipe thread being tapered is prone to this type of damage. Compression, flared, and inverted flare fittings do not seal on the threads so teflon tape is not needed and should be avoided.

Sorry posted the wrong link earlier
Permatex



Also this article may clear things up
How to Properly seal Fuel Fittings and Fuel lines

Wow, this is amazing. I just came back from the local NAPA store where I bought some new fuel lines, fittings and gasket sealers. I had a few minutes to wait while the heat comes up in the shop and I decided to surf Chat for a minute... This topic is EXACTELY what I'm working on today!!!

Let's compare.

When I asked the counter-guy what to use on the gas threads, he said "Teflon tape". I replied "Nope. Did that before and it slowly leaches gas and turns yellow. And the risk of small slivers is too great." I don't do that any more.

Now, I've also tried the natural gas Teflon tape (yellow or pink) and it's way too thick. Don't waste your time.

So then we went on to discuss the Thread Sealer that you have shown above. I have TWO tubes of it in my shop... but it's the older style. I noticed that the new one is now labeled as HIGH TEMPERATURE. So I bought that.

BUT -- if you read the fine print like I did (AFTER I GOT HOME) it says right on the package:
Ooops.

But the good news is that this Thread Sealant is OKAY for use on HYDRAULIC FLUIDS such as your brake lines. (But if your brake fittings are leaking... you've got a different issue.)



Now the old standby that I've used previously (and it WORKS very well) is
AVIATION FORM-A-GASKET.

Here's the A-Ha! moment:
I did not know this, but it's also called Form-A-Gasket Number 3.

THIS is the MANUFACTURERS RECOMMENDED solution for sealing gas assemblies.



--Bill B

Thanks, Bill...Once again, you've saved the day...

Good old permatex #2. Works every time!

Excellent research results and we all get to benefit.

I am not an expert that has extensive personal experience with the subject. Do have many years chemical training and experience to better understand what is being written.

You should note that the Technical Data Sheets for Permatex® Form-A-Gasket® No. 2 Sealant and Permatex Aviation Form-AGasket® No. 3 Sealant state "1. The product can be removed from metal surfaces with isopropyl alcohol. If the sealant has been dried for a long time or at high temperatures, cover the sealant with alcohol and allow to soften overnight." And "PROPERTIES OF UNCURED MATERIAL
Typical Value Chemical Type Modified resin, fillers & alcohol"

I have never tested either with E10 or other alcohol containing gasoline blends so can't advise on longevity with them. But a fella posted the following on a Studebaker site "When I reinstalled the bung in the bottom of the tank, I used a bit of Permtex #3...it's *supposed* to be gasolene resistant. It must not be E10 resistant. Until ths weekend, the tank has been leak free, but Monday I opened the garage door and there was a strong smell of gas. A quick peek at the tank confirmed that there was a slow drip from the fuel tank bung. Everywhere else is dry."

Another person replied "I've been using Permatex High-Performance Thread Sealer with good results. Comes in a larger white squeeze tube with the blue lettering (not the more common high-temperature thread sealant with the red lettering), and is good on stainless fittings, too."

On their website "Gasoila® E-Seal Thread Sealant
Soft-Set with PTFE Non-hardening, non-toxic, opaque, dark green paste designed specifically for ethanol blended gasoline including E10 and E85 (for 100% ethanol or 100% methanol applications - use Gasoila 100)."

Another commercial site "Hylomar Universal Blue is the world standard for a non-setting sealant. Universal Blue is resistant to a wide range of fluids, including all industrial fuels, oils, water and brine, air, turbine and piston engine combustion products, water, water/glycol and methanol mixtures, petroleum and synthetic diester lubricating oils, gasoline, lubricating oils, gasoline, kerosene fluids, and most fluorocarbon refrigerants." Other suppliers offer a blue sealant that I suspect is the same or similar to Universal Blue.

How about good old RectorSeal No.5. Has been around a while.

Chipper, Thank you for sharing this Information and your knowledge with everyone, it has been very enlightening. It also may save one of us from having a fire either on the road or in our garage.
Hope you get your leak fixed without to many problems

RectorSeal® No. 5® is recommended for pipe made of galvanized steel, iron, brass, copper, aluminum, stainless steel, polyethylene, reinforced fiberglass, and PVC. DO NOT USE ON ABS - use RectorSeal® No. 100 Virgin™ or RectorSeal® T Plus 2®. RectorSeal® No. 5® is recommended for pipe carrying:
Gasohol (unleaded Gasoline and 10% Alcohol)