an flare fitting sealing

I have two fuel fittings that refuse to seal. Both are in the engine bay. Both are 6an male to 3/8 steel line with Tube nuts and sleeves.

I've tightened the piss outta them. I've loosened and retightened. I've stared. I've cursed. I've prayed. There is absolutely no reason why they should be leaking.

What can I do? I was thinking of stuffing an o ring in there, but yall usually have better solutions than me.

Got to get these leaks fixed so I can move on to the next step.

Gasoline rated thread sealant?

So this is the flared part of the connection that's leaking? Is the female part a pre made fitting or something that you made up yourself?

did you make your flare deep enough?

Female is self made with a mastercool flaring tool with correct 37 degree flare die. Done exactly the same as the two that don't leak. Male part is a 6an male /male aluminum adapter from summit.

Leak is coming down around the sleeve on both, so it's assumed to be the flare seat itself.

So you have a 3/8 steel tube that you flared, then added one of each of these?

I'm going to guess that if this is correct, that there is a problem with the flare. Not deep enough, not centered, not straight, ect. Or, since you mentioned tightening the piss out of them, the flare could now be split or cracked.

So, a compression fitting? Leave tight come back the next day, crank down some more, repeat as necessary until whatever the fault is deforms under pressure. Or put a little ptfe pipe dope on the ferrule and crank it down. I've got a bottle of Harvey's "TFE paste" in front of me and it says it's good for fuels and oils, so I don't think you need anything fancy.

These work great: http://www.flaretite.com/flaretite.php

AN (JIC) fittings only seal on the flare so thread sealant won't do anything.

In reply to HappyAndy:

Aluminum, but yes.

I took it apart earlier today, thinking burr, crack, etc. None. And the flare appears to be the same size and centered on the sleeve. I'll happily look again though.

Yugo: not compression. Actually a single flare.

Double check that you did not make the flares too deep. The Mastercool kit needs finesse to do the 37 degree flares correctly, you can't just line up the tube with the face of the die like you do with brake line flares. It's kinda sorta halfway maybe.

AN lines don't need to be super tight. In fact overtightening can damage the hardline. This is why brake lines are double flared, folding the tube back over itself makes it far less likely to be damaged, with the downside that a flare is technically only good for one connection. AN flares are slightly different on the male vs. female side so the cup stretches slightly over the cone, this makes for a repeatable seal but being single flare it is also more susceptible to galling/cracking if overtightened.

The more I work with fluid couplings the more I like bubble flares. Baller Me wants to do every connection everywhere with dry break fittings.

They make little flare inserts for damaged AN flare fittings. It's a little aluminum ring. Otherwise, sounds like your home brew part is not to MIL spec.

How can I tell if the flare is too deep?

Try taking the fitting apart clean and dry both sides then color one side with a sharpie. reassemble good snug but not cranked down and twist 10-20 deg remove fitting and check the colored fitting for rubs this should show you where you are and are not making contact.

iadr wrote: ORB for me.

Truer words have not been spoke.