Another week of tinkering.
Managed to get the unions done to the old lines:
These sucked to do. Hah. I wanted to stagger them and get them nicer looking but it's just so tight there, and working upside down isn't my favorite thing.
Front driver side caliper bleeder screw snapped. It was super rusted into place.
I had good luck another time using the milling machine to mill out the old bleeder without killing the caliper threads. I got it to work again but it was much easier last time. Chased the threads with a tap to freshen them up. Seized pretty bad, other 3 were totally fine.
The bleeders are M8x1.0 which apparently none of my local stores carry. And apparently a relatively uncommon size that they're kinda hard to find online. Speed-bleeders, yes. Found the standard ones in a big assortment kit on Amazon but not individually. So I grabbed one from my parts car for the time being
I went to replace the lines on the rear axle, and every flare nut is seized. I tried a lot of PB blaster and some moderate heat and no luck.
With the system sealed and in the interest of feeling like I made progress, I bled all 4 corners with the rear lines as-is and everything seemed to hold, pedal is firm.
I'll test drive it this week around the parking lot. So I may have to do all the lines firewall back at once, depending on how destruct-ey I have to get getting the old stuff apart.
So if anyone's got a decent rear brake junction piece for sale let me know