Well, replaced the master cylinder.  Seemed to be fine but as I used the
brakes, the pedal worked worked down to the floor.  The pedal has pressure
but if you push hard enough (like a panic stop), the pedal goes to a metal
stop which I guess is the top of the brake lever hitting something in the
brake drum or some bracket.  Does anyone have any ideas?  There are no noted
leaks anywhere at present so far as either I or my mechanic can find.  That
indicated the master cylinder.  No I would suspect that power booster.

William