im redoing my fuel system this winter. im going to use braided stainless from the tank to the pump, then im going to use a hard metal line to go to the engine bay. my question is what kind of flare needs to be made to connect a hard line to a -AN fitting. is it just a regular double flare or is there a special tool. thanks alot

 

It's a "regular" flare (usually double), made with a "regular" (not "special") tool.

The tool is particularly designed to produce -AN flares, at their 37° angle. A hardware store or SAE flare tool isn't the right kind. But as far as how it works and what it does, it's "regular", just like SAE flares; just at a different, non-interchangeable, angle.

Alternatively, you can put a 45° SAE flare on your hard line, and use an adapter fitting to get to the -AN stuff.

 

A 45° flare will leak. You need a special 37° flaring tool. These tools are not cheap or easy to find and trying to flare stainless line is very hard. There is an easier way though.

You don't flare the line at all but use a special compression fitting for the 37° AN fitting.

You slide a tube nut over the hard line then slide a sleeve over the line. Tightening the nut will compression fit the sleeve to the line.

http://www.jegs.com/webapp/wcs/store...10002_81658_-1
http://www.jegs.com/webapp/wcs/store...10002_61062_-1

You can reuse the nut as many times as you want until it gets damaged by simply cutting the line and removing it however the sleeve is a one time use item. Once it's compressed onto the hard time, it can't be removed.

 

Also note, important: if the tubing is seamed then ONLY a double flare can be used.

ONLY seamless tubing may be single flared.

98% of the tubing used in OEM brake and fuel systems is seamed. IOW, the tubing is made by folding it over and welding where they meet. Thus creating a seam down the length of the tube. This can be seen as a ridge.

The double flare, where the end portion of the tube is folded back in, will prevent the seam from cracking. Standard industry practice.

Seamless tubing is made by drawing it over a mandrel. Also know as DOM tubing.

As far as I know, AN flares are only supported with seamless tubing. This is because of the additional thickness of a double flare. And as others have posted AN is a 37 deg flare, not the 45 deg used on typical double inverted flare's on cars.

I also believe that compression fittings have no place in a fuel system (or brake system). They leak very easily. Ever see how fast a car burns with a fuel leak, it's scary.

RBob.

 

thanks alot guys, this is exactly the info i was looking for. do those compression fittings meet NHRA standards. i was always taught not to use compression fittings on brakes lines. would it be safe to use them on my fuel system.

 

Brake lines can see up to 3000 psi, that's why they can't use a compression fitting. Fuel systems are less than 100 psi. Normally less than 50 psi and from the tank to the pump is a suction line not a pressure line.

How much pressure do you think that steel braided hose can handle?

 

would it just be better for me to use all braided line. im not looking for a cheap way out. i just want to know the "right/safest" way to do this. thanks alot. all this info is a huge help.

 

When I had a fuel cell in the rear, I ran braided line all the way just because I was too lazy to install hard line. Fuel cell is under the hood now.

 

so basically either way is safe. its just a matter of how much work i want to do. it just a matter of personal preference

 

I believe this is the adapter you need... put a 45° (SAE) flare on your steel tubing, put this on, run your braided line from there.

 

FYI, I cut my hard fuel lines back by the firewall, and Tomorrow I should be recieving my 37degree flair tool and AN fittings from summit, I will be turning my hard fuel lines into a 37 degree flair that AN fittings can screw into. I will be running flex line from there up to the engine. Should be for a much cleaner look.

 

if you can please take some pics. if you dont mind me asking, how much did that tool cost you. thanks alot

 

I will definitely have pictures when I am done and the process along the way. I probably wont have it done for about a week however, But check back, I will post in this thread.
The tool was $32.00 dollars from summit.

http://store.summitracing.com/partde...5&autoview=sku

"Most flare tools are set up to make 45 degree flares for fuel lines and household applications, but these Summit flare tools make 37 degree flares--the proper angle for -AN automotive fittings. These 8 degrees can be the difference between annoying leaks and a perfect seal! A carrying case is included."


Don't know if this applies to you but 3/8 line = -6AN and 5/16 line (our stock return size) is a -5AN.

 

Do you realise that piece of tubing is seamed (the fuel feed & return hard lines)? A single flare is not proper for seamed tubing. The ridge on the inside will make sealing the fitting difficult. And eventually the seam will split causing a leak.

We are talking about fuel lines at a decent level of pressure that will leak A LOT of FUEL. Ever see EFI vehicles when they get a fuel leak. There is nothing left.

I know that it is too late for this since the lines are already cut. But the stock saginaw and inverted flare fittings can be easily adapted to AN. The major AN company's make adaptors for this.

RBob.

 

is this the same sleeve as if you were doing a flare or is it a totally different sleeve?