I hate to admit it, but I have done it both ways.  In retrospect I never should have done the single flaree.  It was a lot harder to get the single flare lines to seal and some times they split.

dan_6776 wrote:

I am about to flare some brake line. I have a flare tool already, but it is not a double flare tool, so it doesn't have the round die pieces that the double flare tool kits have. Will my flare tool kit work or am I just asking for trouble not using a double flare kit? Thanks

single flares should never be used on brake or fuel lines, unless you are using an AN fitting, which is 37 degrees. A/N fittings are 37-degree single flare (A/N standing for Army/Navy as these were military spec.)

70XL wrote:

I believe the single flare is for Stainless Steel lines and the double flare is for mild steel tubing. They are different angles, as well, so not interchangable, in my understanding.

You have been misinformed. There is a lot of wrong information on the internet regarding this, and shoddy mechanics as well will tell you the wrong thing to make it easier for them to get away with poor workmanship

to be perfectly clear:
All auto lines require a 45-degree double flare, regardless of stainless or mild steel brake lines.
ALL OE brake and fuel line parts (wheel cylinders, master cylinders, fuel fittings) use a 45-degree double flare.

Z.

 

Last edited by zray (June 5, 2014 6:23 am)