I respectfully disagree with Denny. I've run and replaced lines on a lot of vintage vehicles, and have written several tech articles on the subject, plus talked with most or all of the industry suppliers for repro brake and fuel lines: Master Power Brakes, Inline Tube, Classic Tube, Stainless Steel Brakes Corp, Baer, etc.
The brass fittings ARE reusable. The tube flare seats down on the nipple inside the brass fitting, and laps onto it. That is where the seal is made. Steel is much harder than brass, and if you don't make the flared end on the steel completely flat with the flaring tool, you will destroy the nipple inside the brass fitting, as it will collapse or deform from the force of the steel tubing. The brass nipple will NOT deform or move the steel.
I have gotten the odd brass fitting that has the nipple crushed--they're junk at that point, and won't make a good seal.
A lot, if not most, of the brass fittings are unique to specific applications: for instance, the junction block on top of the rear end housing. Your local parts store isn't going to have that one. A lot of fittings are also manufactured with some sort of provision for securing the fitting to the chassis, with either a tab for a bolt, or grooves for a clip (such as the front line fittings, where the hard line goes into a tab welded to the frame, and the rubber line to the wheel goes in from the other side). When I go to junk yards, I like to grab a couple of these kinds of fittings from different vintage vehicles--they come in handy. 90-degree and T-fittings particularly.
It's not uncommon at all to have leaking fittings after a complete rebuild. The fix is very simple: rather than crank down the union and tighten the beejeezus out of it, instead back off the nut and snug it up, repeating three or four times, then firm it up and call it done. This will seat the flare on the brass nipple, lapping it in. I've had your same problem time and time again, and this fix has worked nearly every time. I learned it from one of the brake line companies, and have used it on my '54 Buick, '62 Suburban, two Dodge Dakotas, and the brakes on my dad's boat trailer. Before I learned that tip, I cranked 'em down like you are.
If that doesn't fix the leaks, take it apart and look at the nipple inside the brass--if it's crushed, distorted or has a huge gall across it, you'll need a new fitting. I've seen one completely crushed, and another with a huge gash across it like a piece of debris was smashed in it.
This months' issue of Hot Rod Deluxe magazine has a story on bending and flaring your own lines.
-Brad
