I'm still around and still working on my old cars.  My 56 Fairlane has drum brakes, I had them rebuilt,  It is a vacuum assist system.  When I first start the car the brakes are horrible, but after a couple of miles the car will stop on a dime.  I suspect the vacuum cannister is bad or out of adjustment.  Can I adjust the cannister?  any ideas would be greatly appreciated.
John