Metal fuel line from carb to pump...I am over it.

Satan himself made this line. I have a repro (looks great) stainless line on my 1970 350. It never seem to fully seat or seal. It seeps past the fitting, not the threads. I had to remove it when I did my timing cover gasket recently. Now it drips. It is as tight as possible, still drip drip. From what I gather, stainless is the issue. Is there a regular steel one put there that you guys know of? I want function over form at this point, and need the easiest and quickest solution. I can deal with fluid leaks, but gas is a different story.

 

I bought a coated steel line (not stainless) of an appropriate length at Advance Auto and used a tubing bender to fit it. Since it had fittings on both ends, I didn’t have to flare them. Hasn’t had an issue in 4+ years of usage.

 

It isn’t seated properly, loosen it up and re align it then tighten.

 

I will try it. After all, that is free. Fingers crossed.

 

Assuming the flares were properly done (inspect), might take a little tweaking of the bends to make sure the line is going in straight. Tightening only one end first before even attempting to thread the other might help show the problem.

 

Being it’s a flared end (metal to metal) the contact point has to be damn near perfect BEFORE the nut tightens up against the flared end.

 

I had the same issue awhile back, only it was down by my stock fuel pump, never did figure it out, and i critiqued the flared end and the pump, it still puzzles me

 

I found out when I put SS brake lines in my car how much harder SS is to compress then mild steel!

I can only imagine how much force it takes to compress the added crush area of a fuel line to get it to seal up!
I would not be a bit surprised if you stripped out the the Female threads on either end that it goes into.

If it where me I would buy a steel female flare seat union , clamp that in a vise and tighten up each end of the line in it until you saw a good contact pattern.
This will save your fuel pump and carb from stripping out.

 

I've used stainless for a long time and I believe the key is always going to be the use of quality hydraulic fittings first, and the precision of the flare second. None of this compression fitting BS.

However, I am a firm advocate of Nicopp tubing for hard lines in automotive use. It's easy to bend and doesn't corrode. I think it's only fault is that if you overtighten the fittings they can shear the flare off the end of the line because it is soft. You might try that.

Jim

 

Take the line off and put it back in the flare tool. Don't cut it off and start over, just try to reform it some. Aka tighten it as hard as you can..

 

I have a flaring kit comes with a countersink on a handle to cut the seating area of the flair. No leaks.

 

I'm doing my own brake and fuel lines right now in Nicopp and agree with Jim that it's nice and easy to work with. I've never made stainless hard lines, but I can definitely imagine how much more of a pain it would be!

Nicopp is also cheaper, so more material to practice flares on before I start on the actual lines. Only downside I see is that Nicopp comes in a roll so you need a tubing straightener if you want laser straight runs, but these can be had for not too much ($100 or so). Worth it if you're redoing a bunch of lines like me.

 

I loosened the line up at both ends, and wiggled it around. Tightened the pump end up first, then the carb end. No leaks, until the next time I touch it.

 

That's the correct way to condition stainless steel lines. I did that on all of my brake lines and zero leaks. They don't have to be tightened any more than steel lines if done correctly.

 

Also I would advise against using plumbing flare fittings. The hydraulic fittings come with a sleeve that sits against the flare and holds it straight in the nut. More critical to align straight with the fitting but once you do it is almost guaranteed to seal properly, and if it doesn't it's usually a faulty flare. Also never attempt to "stretch" a line. It should have a bend or two in it to allow it to flex with temperature changes. I've run everything from 3/4" down to 1/8" and done properly it is extremely reliable.

To straighten Nicopp I roll it out on a bench, hang the coil over the edge, rotate it and check it against a straight line and the flatness of the bench. You can get it so straight it's very hard to see any bends looking down the tube and it's never going to stay quite that straight during install anyway.

Jim

 

Why I use the standard steel,....they lasted for 60yrs in harsh elements,...they'll last 120 in a nice rarely driven in nice weather elements

 

I've noticed on a couple leaking fittings , after probably over tightening and still leaking , the female threads are cut different in similar fittings . Some are not cut deep enough and the male threads stop before the tube flare is fully contacting inner angled surface .
I noticed because on one it was straight and fully tight but the tube would still "jiggle" a little .

 

Folks may or may not inspect the FLARE, but they almost never look inside the fitting to check-out the flare seat.

REALLY common for them to be brutalized due to over-tightening a misaligned tube.

There are copper sealing washers for flares. I've never used 'em (never needed 'em) but they do exist.