To flare, or not to flare...... thats the ?????

[Ducman82]

so im going to relocate my 2 micron fuel filter to down on the frame. my question for you guys is should i use a AN style flare on the hard line ( i have the tool for the 37 degree flare) or should i use a compression style fitting?

 

[Jim W]

I do not like flare fittings. You can not prevent them from leaking if one develops a leak. Look at the geometry of a 37 deg fitting; as you tighten the fitting the 37 deg flare will spread the tube assembly apart more and continue to leak. I would look at using a hose assembly with an O-ring style fitting that you should be able to buy from a truck parts store. You might be able to buy one from a equipment dealer such as Cat or John Deer. They will make hose assemblies for you that are compatibly with diesel fuel.

Just my $0. 02.

 

[JJPage]

If the line was copper... . flares are fairly simple, but I am not sure you will get a good seal with the steel line. I thought about flaring the line also, I have all sorts of fittings from my HVAC days.



I ended up just using Parker push-loc fuel line with a hose clamp over the steel line, and used the push-loc fittings in the filter head. It has been fine, no leaks.

 

[CumminsBu]

Flare it, steel line is ridge even to hold low pressure.

 

[Ducman82]

hey, is the 3rd gen metal fuel line 3/8???

 

[nickleinonen]

flaring steel/stainless steel line to jic 37° is no problem. it is a clean job if you run it nicely, but it is a pain in the butt to run hard piping at times.

are you going to use the stock lines? compression fittings are much quicker and can hold the same pressure as a jic. they are used in hydraulic systems running at over 2500psi.



a jic 37° flare will seal as well as a 45° sae flare, the jic is just rated for higher pressures.



the only bad thing about any flare fitting [jic/AN & sae] is that if you loose torque on the tube nut it will leak. with something that uses an o-ring [orb, orfs, flat flange] even with it loose a little bit they don't leak as the o-ring compresses when torqued and when it loosens off a little, it still will seal as the o-ring will un-compress to take up the slack.

 

[champspa]

in refrigeration we use these gaskets for flare fittings.



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# 4 Flare Gaskets </TD></TR></TBODY></TABLE></TD><TD><TABLE cellSpacing=0 cellPadding=3 width=300><TBODY><TR bgColor=#ffffff><TD vAlign=center align=middle width=100>[FONT=Verdana, Arial, Helvetica, sans-serif]#ad
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# 6 Flare Gaskets </TD></TR></TBODY></TABLE></TD></TR><TR vAlign=top align=middle><TD><TABLE cellSpacing=0 cellPadding=3 width=300><TBODY><TR bgColor=#ffffff><TD vAlign=center align=middle width=100>[FONT=Verdana, Arial, Helvetica, sans-serif]#ad
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# 8 Flare Gaskets </TD></TR></TBODY></TABLE></TD><TD><TABLE cellSpacing=0 cellPadding=3 width=300><TBODY><TR bgColor=#ffffff><TD vAlign=center align=middle width=100>[FONT=Verdana, Arial, Helvetica, sans-serif]#ad
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# 12 Copper Flare Gasket </TD></TR></TBODY></TABLE></TD></TR></TBODY></TABLE>

 

[nickleinonen]

that looks very similar in concept to this:

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if you have free time, there is some good reading at the hydraulic supermarket.

 

[Ducman82]

Ya i decided to flare stainless line and the stock lines. i spend the buttload of money on the flare too from eastman so i might as well use it. one thing that will work is the stock line mounts. on thing i did fing out, is while i was having my tires rotated i looked under the truck and realized that short beds dont have much room on the frame for the filters i want down there... so... im going to build a mount off the transfercase skitplate/ mount. should be fun. i plan on doing a write up on the project.