Fuel leak on a 67 427 Tri Power carb fuel line.

[Mark F.]

I own a 1967 427 tri power and it has developed a leak where the fuel line screws into the center carb. The fuel lines were fairly old so it was suggested that I install all new fuel lines since the flair on the end of the fuel line can lose it's shape over time and not seal properly. I put new fuel lines on and the leak is still there, same place. I am wondering if the problem is with the seat of the carb housing that the flaired end of the fuel line interfaces with?

Any comments or advise would be appreciated.

[Thomas N.]

Re: Fuel leak on a 67 427 Tri Power carb fuel line.

Mark
There is a possibility that the fuel inlet fitting is scored. Parker makes copper flare gaskets that are soft copper and seal up irregularities between the mating parts. I'd buy some of these and use these. The brass blocks are known to get scored up because of the very differences in hardness between the soft brass blocks, and the steel flared fittings that get work hardened during flaring. Here's a link to these from Grainger.
These are 3/16". I don't have right at my fingertips what the size is, but this will give you the idea. I'm sure someone will chime in on the size.
P.S. I now use these all the time on vintage flared fuel fittings.

https://www.grainger.com/product/PARKER-Flare-Gasket-5WRW0?ef_id=Cj0KCQjwxJqHBhC4ARIsAChq4atXsJOTgF4EM_kcJpfHRaNJjUixAj8ihVonz3DC3GURBofy3a7l99MaAkNsEALw_wcB:G:s&s_kwcid=AL!2966!3!493995555568!b!!g!!&gucid=N:N:PS:Paid:GGL:CSM-2296:9JMEDM:20500731&gclid=Cj0KCQjwxJqHBhC4ARIsAChq4atXsJOTgF4EM_kcJpfHRaNJjUixAj8ihVonz3DC3GURBofy3a7l99MaAkNsEALw_wcB&gclsrc=aw.ds

[James N.]

Re: Fuel leak on a 67 427 Tri Power carb fuel line.

Well, sometimes those old fuel fittings just don't come together as they should. I have had good success in stopping slight leaks by applying an itsy, bitsy bit of grease on the male fitting thread which allows me to give it an extra hair of a turn when tightening down. Be careful not to get grease on anything other than the threads on the male fitting, and use it very sparingly. Also, it's a fine line between just tight enough and stripped threads on those pieces! So you may have to do the tighten, check.....re-tighten, check....re-tighten, check routine.

[Gary B.]

Re: Fuel leak on a 67 427 Tri Power carb fuel line.

As a thread lubricant for fuel and brake line connections, a lot of people, myself included, are fans of EZ Turn. Same rule applies as what Jim said. I apply it meticulously and sparingly to the male threads.

https://www.chiefaircraft.com/ez-turn-5oz.html

A 5-oz tube will last you a lifetime. Several membears of my chapter have shared the same tube.

Gary

[Tom L.]

Re: Fuel leak on a 67 427 Tri Power carb fuel line.

+1 on the copper gaskets. I used them on my car for the same reason. Steel lines lose their "crush" after being taken apart and re-assembled a few times. The copper gaskets are made for that purpose. Because in the refrigeration and A/C world there are often components made of steel and other hard metals that meet one another with flare connections it's important to use them, new each use, when joining these components. They are widely used in refrigeration and A/C applications but you won't find them in your local hardware store and probably not a plumbing supply. If you need help getting them let me know. Have fun!

[Daniel S.]

Re: Fuel leak on a 67 427 Tri Power carb fuel line.

Have had the same issue on my '68 L71. Just a couple of the Holley inlet fittings have given me troubles. Lightly apply some liquid teflon on the offending male treads always seems to work. Emphasis, apply lightly and not at the lead edge of the threads. Also, make sure to thoroughly clean old sealant off the threads whenever they are removed for servicing the carbs.
Loctite 592 is a good choice but there are others that will work as well.

51Z6hsuG2aL._AC_.jpg

[Jeff C.]

Re: Fuel leak on a 67 427 Tri Power carb fuel line.

1963 340HP filter to carb fuel line leak. New fuel lines from a good source. Could not stop leak. Tried sealant, line adjustments, every thing else I could think of. Read a post about copper washers. Went to ace hardware and found correct od copper washer (not bronze) installed in both ends of line. Has never leaked since.
Jeff

[Duke W.]

Re: Fuel leak on a 67 427 Tri Power carb fuel line.

Remember that the seal with flair fittings like brake and fuel lines is between the male and female surfaces. Nevertheless, I see Teflon tape on the B-nuts all the time.

I've always found that with new fittings it's best to tighten/loosen three times to "mate" the surfaces with a final tightening.

If that doesn't work a soft copper gasket of suitable size will often do the job. Buy some spares in case you ever have to disassemble that joint again.

Once you get a flair fitting to seal they will usually never leak unless disturbed or damaged.

Duke

[Gary B.]

Re: Fuel leak on a 67 427 Tri Power carb fuel line.

1963 340HP filter to carb fuel line leak. New fuel lines from a good source. Could not stop leak. Tried sealant, line adjustments, every thing else I could think of. Read a post about copper washers. Went to ace hardware and found correct od copper washer (not bronze) installed in both ends of line. Has never leaked since.
Jeff

[Mark H.]

Re: Fuel leak on a 67 427 Tri Power carb fuel line.

On my '64 L75, the 4 fittings from the fuel pump to the carb are 5/16. The fuel pump inlet pipe is 3/8.

[Gary B.]

[Thomas N.]

Re: Fuel leak on a 67 427 Tri Power carb fuel line.

Hi
For a 3x2 setup, you need 3/8" flare gaskets. Parker part number 2GF-6, grainer part number 5WRW3.
Link to the 3/8" is from Grainger.

https://www.grainger.com/product/PARKER-Flare-Gasket-5WRW3?searchQuery=2gf-6&searchBar=true

Like Gary said above, I just sent a link to show what these are, not the size in question.