Just a follow-up to my post of Sep 9. I promised to get back to those who so kindly responded to see which advice worked.

Somehow I felt the problem was in the booster or master cylinder, so I bled the master cylinder to no avail. Next I turned my attention to the linkage. The Haynes manual says "remove the pin and yoke (which connects the thrust rod to the brake pedal). Right! I want to meet the alien who can get his fingers up there to that...on second thought. Anyway, I removed the master cylinder, then disconnected the booster. I attempted to pull it away and discovered that pedal yoke rod actually screws into the thrust rod..and there is a lock nut. This suggested adjustment to me so I undid it a couple of turns (about 1/2" increase in length) locked it back up and reinstalled.

Then I put the master cylinder back on (getting those two flair fittings started was a bear), re-bled it (let the juice drain out through the fittings by gravity while tightening them, topped off the fluid and gave it a try.

What a difference. I now have a hard pedal. Apparently whoever did the original restoration must have removed things and not adjusted that rod properly. I assume the master cylinder piston was not applying full pressure to the system.

My guess is there's some metric for the extension of the front of the thrust rod out through the hole in the front of the booster unit. Wish I'd had that specification so I could have done this 100% properly. In any case, until disabused by one of you out there that I've put my life in peril, I'm going to enjoy my new, hard brake pedal.

And yes, I did flush the rest of the system. That one-man bleeder from IPD really works quite well.