I just went through this on my BN2. My usually reliable pressure bleeding--about 10psi at the reservoir--and old-fashioned 'pump the pedal then hold while I bleed' method did not work (pedal would go too far to the floorboard). I posed the same question to an email group with a couple thousand members--at least, it used to have that many--and got many suggestions, but still no hard pedal (pedal would go to the floorboard if I mashed on it). One person suggested holding pressure on the pedal for a period of time; frustrated by all other attempts I found a suitable piece of wood and backed it up with the driver seat pan, holding firm pressure on the pedal (I'd heard of this 'technique' before, but had never needed to try it). I had other things to do: moving out/in, harvest, taking car of my mom and remodeling her house, etc. and left the board in place for a few weeks. Lo and behold when I next tried the pedal I had a good pedal, at least for a drum brake car: Pedal would go about halfway to the floorboard and hold firm, brakes were as good as you can expect from drums (as drum brakes go, Healeys are pretty good; our '65 Mustang had smaller drums on a heavier car). I have no idea why this can work; possibly the pressure causes air bubbles to form and float up into the reservoir. I'm using Castrol DoT4 'Synthetic' (all brake fluid is synthetic, the companies appear to be cashing-in on the cache' of synthetic oil).
I don't understand this: 'I do have stainless steel brake lines from two of out the three connections, right front still has the rubber hose style.' There are, if I've counted right, 6 or so hard lines: reservoir to M/C (not pressurized), M/C to junction, junction to FR and FL, long line from junction to the rear axle 'T,' T to each rear brake. The front brakes have a short line from one slave cylinder to the other, which can be difficult to get bled. The fronts have a flexible line--braided/reinforced rubber to each drum--since, well, it's advantageous to be able to turn the front wheels.