Originally posted by Peaty
That's what I was trying to find out, if it's just the nut part on the hard line (the part in the pic below where the flair nut wrench is on) you might still be able to get it tight enough, if the mating surfaces are smooth and un marred. The problem is the nut material is soft, you don't want to squish it. Even if it's rounded you may be able to get a grip on it with some vice grips and get it tight enough to stop it leaking and get it to a garage to have it fixed properly.
My tech knowledge is not great enough to understand the whold compression fittings end of this, but the nut is as tight as I can get it (and dang, does it look shiny after being ripped up from my Robogrip!). I did just look at it again and notice that there is a little bit of brake fluid on the top, too (where the arrow points in Peatey's image above), although I don't know what this means.
There are a few brake places a short distance from here, and assuming I finish my front brakes (Stoptech kit - I must be crazy to try this all, but the instructions make it look easy), I can downshift and ease my way to the place. The rear lines are Stoptech also and appear to be the right sizing...