Had something happen that never experienced before.  Brake pedal went to the
floor.  NO BRAKES!  Checked fluid, level fine (clutch still working properly
on manual trans).  When start engine, pressure on pedal drops to almost zero
(meaning that vacuum is getting to brake system).  There is a feel in pedal
almost like something like a bolt or spring is being scraped and at the
extreme limit, there is a little brake action.  Can anyone explain this type
of failure?

William