Fuel line flare

I agree with those who are telling you...NOT ...to use Teflon tape. However, if you want to use something to help ensure sealing against gas leakage, I use Permatex Thread Sealer. Gas does not affect it and the seal is great, in my useage.
 
I tried it again, seems to be working now except for a very small drip forming on nut at the connection to sediment bowl. I tightened it really tight but worried about splitting the casting. Anyway, hopefully it holds now.
Tom, I believe you were right, it just wasn't being tightened enough for the ferrule to do it's magic.
Hardtimes, I was just going to ask what to use for threads on fuel connections. Thank you for the suggestion. Just one last question, is Permatex a paste, liquid or tape?
Thank you all for your help.
 
If you're still getting a seep at the carb end after it is tight,take the line back off and look close at the seat where the ferrule rides.It may well be pitted.You will need a good magnifying glass and a light.If it is you can reach in the hole with a 7/16 round stone,for a Dremel or the like,and clean up the seat.Just touch it,don't try to really remove material.
 
do not use Teflon tape, it will possibly get into your fuel flow and really gum things up. bad stuff
 
Here is a good example of what can happen with Teflon tape. You can see the remains of the tape around the outside threads on this solenoid fuel shutoff valve. But when I took it out of the car I found small bits of Teflon tape inside the valve. You can see them in this photo. The ones you can't see were down in the carburetor. Not OK.
 

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I don't use teflon tape for anything, it causes more problems than it ever solved for me. If you must use some type thread sealer, Permatex high tack sealer comes in a can with a brush applicator and works good for me. The fuel line from the sediment bowl to the carb should need no sealer because it depends on the ferrules to seal .
 
I make it a practice to wrap Teflon tape around the ferrule on each end of the fuel line when ever I have it off. I have it off often to road test Zeniths. Over repeated use the ferrule gets whacked out of shape and the tape makes for a good seal. I don't see how the Teflon tape can migrate past the ferrule and into the Zenith and I have never had a problem with it. I would never put it on the threads as they are not part of the sealing action.

Tom Endy
 

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If you are still getting a drip and the ferrule is good, you might need to trim/file the line a little shorter in front of the ferrule. A line that is too long won't allow the ferrule to seat in the carb end when proper torque is applied.
 
Tom Endy said:
I make it a practice to wrap Teflon tape around the ferrule on each end of the fuel line when ever I have it off. I have it off often to road test Zeniths. Over repeated use the ferrule gets whacked out of shape and the tape makes for a good seal. I don't see how the Teflon tape can migrate past the ferrule and into the Zenith and I have never had a problem with it. I would never put it on the threads as they are not part of the sealing action. Tom Endy
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Good on you, Tom! I completely agree with you! Teflon tape works and if used as you describe, it never gives any problem.
 
We used Teflon tape all the time on our hydraulic cylinders we built. The trick is to start the tape one thread back from the end of the fitting. Then rap it so when you screw it in it does not unwrap it. For a right hand thread rap it counter clock wise from the front to the back of the fitting.

Of coarse you would not use it on the gas line fitting, would not be the right place. You would do it like Tom does. Put it on the sealing surface. Just make sure it does not go beyond the end of the ferrule. Stay back just a little.
 
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Sometimes it's the simple questions that generate the biggest teachings. Since Tom Endy posted there's many that are thinking, "hmmmm, I always thought Teflon tape was a bad thing" :rolleyes:
 
I have heard that Tom Endy does good carb work but I don’t think his Teflon tape recommendations are for everybody.

The gas lines use compression fittings. The compression fitting system has been around for a long time and it works well when properly tightened. It does not need extra sealing unless the parts have been used before. When a new ferrule is used the first time it is compressed to match the machined surfaces on both the nut and the carburetor port, and it is also squeezed tightly onto the tube. In the process, the ferrule surface gets fitted to that particular nut and that particular port.

If you use that tube in another carburetor the fit will be different. The ferrule has already been compressed and work-hardened and it will not adapt to fit the same. It will leak.

Tom, when you use the same tube to test several different carburetors you may need the extra sealant to keep the joint from leaking. But in most situations the Teflon tape is not needed and it definitely does shred and the pieces do get where they don’t belong. I think it should be kept for water pipe joints.
 

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I wouldn't use Teflon tape or permatex sealer either. If the ferrule is damaged from use, get a new ferrule. Sealer is a band-aid that shouldn't be needed.
 
I agree, I use no sealer of any kind where ferrules are used. For other applications where a gas tight sealer is of benefit such as in where the cut off valve screws into the gas tank, I like Permatex high tack sealer. I don't even use teflon tape on my home plumbing repairs, I use pipe dope in a tube . Particals of teflon tape will get inside the carburetor and cause problems. I've also seen teflon tape cause fittings to crack or strip in some applications. I just don't use it .
 
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