1962 crown convertible power brake booster

[jrcollins1962]

Anybody out there with some detailed knowledge of the Bendix double compartment brake booster used on the 1962 models? My booster and brakes were working normally. When the booster began leaking vacuum I sent it off to Ft Worth and had it rebuilt. It came back with no leak, and with what I believe to be proper movement of the rods (when you have vacuum hooked up and the booster is loose, you can push on the inner rod, and the outer rod moves the SAME amount, and both rods return to the original resting position when pressure is taken off the inner, pedal rod). My problem is that now the booster, or something, applies the brakes 100% even with the slightest pressure on the brake pedal. There is no "light braking". It is either "nothing" or "locked up" brakes. The shop that did the rebuilding has been anything but helpful with the problem. The front rod had a projection of 1 3/16", and the acorn nut had maybe 11 threads showing when taken off the car. It came back from the shop with a 1 5/8" projection and slightly crooked front rod. I screwed the acorn nut in to get back the original 1 3/16" projection, and put it back on the car. I have tried at least 5 different projection lengths of the outer, front rod but all have resulted in the same 100% braking with the slightest touch of the pedal. The master cylinder appears to be in working order except for a slow seep, and was working fine before the rebuild of the booster. The booster's outer check valve appears to be fine (can suck in air but not blow into it , or is it vice versa?). Does anybody know if the booster is supposed to provide a proportional (non- linear) braking action (rod movement) as the pedal is depressed? Any ideas you may have on the cause of this problem will be greatly appreciated.