Picked up a cheapo 37 degree flare kit from summit racing for my brake lines and after some fiddling Ive got this: 
The only thing that makes me unsure is the last picuture. I thought the flare was supposed to cover the entire angled part on the union
Seems fine. The flare is only going to contact in a very small area. If you take a male and female 37° flare fitting and sharpie the male end then torque them down it will only show a thin line worn away when they are taken apart. The tubing is also soft so it is going to compress into the flare to seal it.
It's hard to tell, the second pic looks like a double flare.
"Brake line flares" are 45 degree angle and are a double flare, because it needs the double thickness to handle the twisting loads of the tube nut acting directly on it. They also "crush" to seal and are supposed to be one time use only, which is fine for mass produced automobiles, for which brake hydraulics are expected to be life-of-car.
37 degree flares, aka AN flares, are a single flare, they use a female threaded nut and a ferrule that the nut pushes against. They seal by having a slightly different angle than the male component, so the flare stretches slightly to seal. They are more expensive because of all the extra components, but they are intended to be disconnected and reconnected multiple times.
You'll need to log in to post.
