I have a 52 with Bendix brakes and there is an adjustment called for in the Factory manual to 'set' the pivot pin. I don't know if 54s have the same procedure. This procedure centers everything up prior to adjusting the wheel brake cylinders. Do you have new brake fluid? Do you have new soft brake lines? A clog will prevent fluid from returning to the master cylinder, leaving the wheel cylinders in the partially engaged position.
Carl

1952 5-window - return to "as built" condition | 1950 3100 with a 235 and a T-5 transmission