The Hydrovac is basically an early brake booster which simularly works with vacuum. They actually have rebuilt ones, somebody told me, at Napa. I know you can order them, probably thru a local brake shop. The only problem is..is without a core, they are a bit pricy...so I hear. I haven't purchased one yet.
Mine on my 47 Deco COE is actually located at the rear of the drivers side of the cab. Black cylindrical can about the size of a small bucket.
If this isn't 'clickable' then copy it and type it into the address bar of you internet explorer.
http://vehiclesofvictory.com/wp-content/uploads/2009/04/chevy-hydrovac1.jpgMaybe somebody will post a picture of one mounted.
