Tricks I learned about 45 years ago in my youth, helping my father restore (for then, even) antique Studebakers for show, when it comes to brake lines and things like the brake line flare nuts that screw into the wheel cylinder or the screw(s) that hold the hard brake line clamp(s) to the axle/frame rail.
For the brake line flare nuts (applies to either reusing the original steel brake lines, if serviceable, or new line assemblies and flare nuts) into new/rebuilt wheel cylinders, pull back the flare nut and put a tiny dot of antiseize on the inside of the bevel of the nut and on the threads, then another dab on the line between the flare and the nut. Put the flare of the line into the wheel cylinder, start the threads of the flare nut and tighten down. No antiseize will enter the brake system, but the next time you or somebody else goes to disassemble it, you or they will be thanking the person that did it and it won't be all corroded together.
For the screws that hold the line clips, thoroughly clean the hole with brake cleaner, blow dry, dry chase the threads with a tap, then use the stainless steel thread equivalent fastener and a dab of antiseize on the threads when reassembling. So much easier to take apart next time and the stainless steel fastener won't rust-fuse itself into the hole.
Are you replacing the hard brake lines? What kind of shape are they in after all these years and climate exposure? Just because they look "good" on the outside doesn't mean that they're not corroding away from the inside, as brake fluid is hydrophilic (sucks up moisture/humidity right out of the air and easily adsorbs liquid water) so any past water contamination will start to corrode the inside of the hard lines, especially if it has been sitting for extended stretches of time. I would highly recommend just replacing them all with stainless steel lines (try SSBC for correct lines, they have the patterns for thousands of vehicles. They even had the correct, complete set (front, rear, chassis, master cylinder to proportioning valve) for my ex-GF's '68 Cutlass convertible when I converted it from straight 4 wheel non-power assist drums to power disc front/drum rear using all GM correct parts. There is a difference in the chassis line and MC to prop. valve line between convertible and hard top/coupe because the convertible frame is double channelled for additional strength and SSBC had the correct convertible lines back in 2008 when I did the swap. For some reason when I look at your post above, there are no photos. Just unlinked URL's on my Android-based phone.
Anyway, just my two cents worth for the cause.
