Has anyone successfully used one of these flareless 3/8 to -6an hardline screw adapters for the fuel lines?
According to the posts i have seen, everyones saying it *should* work but id like some empirical evidence from someone whose done it.

 

Yes they work and used them on my car. However if you are stock fuel hardline you will want to use 5/16 adapter.

 

 

I used these to adapt the hardline to 6an
https://www.jegs.com/i/Vibrant-Perfo...16445/10002/-1

 

I used the same one as Mike93r1 posted above.. Worked great.

 

Hey yeah after a bit more research it seems like you want the -5an and then step it up to the -6an

 

 

5/16" is the factory line size. I am considering cutting off the factory flares, flaring to 37°, and then using standard -5AN to -6AN m-m adapter.

 

Will this work for high pressure ac lines?

 

Absolutely not.

 

For added safety with fuel lines

Or on high pressure lines like AC you can use Swagelok double ferrule fittings.

You always use fittings/ferrules made of a harder metal than the line you are adapting to because the ferrules actually swell the line to make the seal.

Also, the FD fuel lines aren't 5/16" (0.3125") they are 8mm (0.315").
Swagelock is available in Metric sizing and precise enough fit that it will matter (won't be able to get the 5/16" ferrules onto 8mm tube).

I have used Swagelok in high pressure industrial applications with caustic chemicals and on my FC fuel hardlines to convert to -an fittings.

https://www.swagelok.com/en

On NPT fittings you want the female end to be the stronger material, so I chose 8mm tube to 1/4" female NPT stainless fitting and then used standard Aluminum male 1/4" NPT to -6an adapter fittings.

https://www.swagelok.com/en/catalog/...art=SS-8M0-7-4