Fuel line isn’t sealing

[Cantedvalve 128]

Pump to carb hard line isn’t sealing at all. When the engine runs, it leaks.  It is a new stainless steel line, but a used pump. Pump had an inverted flare to AN fitting on it before that gave no issues.  I’m wondering if it isn’t the fuel line itself.  I’ve read that double flared SS is not a good idea... which is what this is.  Maybe cut off the double flare and put on a single?  I don’t want to go back to braided line.

[barnett468 418]

 

exactly where is it leaking?

double inverted flare on stainless is fine . i have used those lines a bazillion times but they sometimes need to be tightened then loosened slightly then tightened etc several times before they seat. grease on the threads and sealing surfaces also helps during this process.

it sometimes helps to use a special "conical" sealing washer on them.

 

 

                                                                      

 

[Cantedvalve 128]

Fixed.  I tool the line off, annealed the flare (got it glowing cherry red and let it air cool), and then did the triple torque technique you outlined.  I only ran the engine for a minute, but with RPM, and no leak.  That is also how I did my stainless brake likes... annealed after flaring.  

Let’s hope it stays that way

[barnett468 418]

13 minutes ago, Cantedvalve said:

Fixed.  I tool the line off, annealed the flare (got it glowing cherry red and let it air cool), and then did the triple torque technique you outlined.  I only ran the engine for a minute, but with RPM, and no leak.  That is also how I did my stainless brake likes... annealed after flaring.  

Let’s hope it stays that way

that's a good trick as well. i have had to tighten the fk out of some of those sob's to get them to stop leaking.

 

[Her69fastback 3]

If I’m not mistaken AN fittings take a 37 degree flare . That maybe why it’s not sealing 

[1969_Mach1 333]

Yes, AN is 37 degrees and seal much better with less torque on the fitting than inverted flare which is 45 degrees.  I fought inverted flare fittings on my fuel lines for years.  They would seal fine, then will not seal the next time a fitting was disconnected and reconnected.  At least so far, no more leaking issues since switching to AN fittings.

[Cantedvalve 128]

I dunno.  It is the standard fitting on the fuel pump.  I am guessing inverted flare?

[69volunteer 84]

I believe you discarded the AN fitting an bra

3 hours ago, Her69fastback said:

If I’m not mistaken AN fittings take a 37 degree flare . That maybe why it’s not sealing 

I believe you discarded the AN and braided line and going with 'factory'.

 

Barnett--i like those fittings. Do you have a source?

[JayEstes 172]

Yes, those copper conical washers are "flare savers".  They are used in AN fitttings.  I don't have much experience using them, but they might make a good solution for sealing stainless lines.  You have to keep in mind that the male side of these things is BRASS (e.g brake distribution block), so when you just tighten the F out of them, you can damage the brass parts (it's not cheap to get a new one either).  This is one of the most commonly reporting problems with stainless lines is the double flares don't seal well (stainless is stronger & less ductile).  I think the flare saver is probably the best idea.  It's softer than brass, and will conform to both the line and the mounting surface without damaging either.  For me, I'm sticking with the softer steel lines that seal more easily.

[barnett468 418]

26 minutes ago, JayEstes said:

Yes, those copper conical washers are "flare savers".  They are used in AN fitttings.  I don't have much experience using them, but they might make a good solution for sealing stainless lines.  You have to keep in mind that the male side of these things is BRASS (e.g brake distribution block), so when you just tighten the F out of them, you can damage the brass parts (it's not cheap to get a new one either).  This is one of the most commonly reporting problems with stainless lines is the double flares don't seal well (stainless is stronger & less ductile).  I think the flare saver is probably the best idea.  It's softer than brass, and will conform to both the line and the mounting surface without damaging either.  For me, I'm sticking with the softer steel lines that seal more easily.

Good point and I meant that i had to  tighten the f out of them even when using the washer. I didn't do that without the washer.

[Mike65 475]

I will be using NiCopp line for my fuel & return lines.

[JayEstes 172]

12 hours ago, Mike65 said:

I will be using NiCopp line for my fuel & return lines.

My buddy used that on his 55 packard  and that stuff is fantastic!  For fuel- quite a bit better than a steel line.