We also broke are Sears 3/4 Breaker Bar in half trying to loosen
our 46mm nut on our Splitty Bus.  If you have one of those axle nut
tools, and your brakes wont hold the wheel still, try this trick.
         Jack the car, put a cinder block underneath, take off the wheel.
          Take out the cotter pin, 
          Screw 2 of the lug nuts back into the drum a good distance
          Get out the factory bus Jack, the longbeefy one
          Angle ii between the two bolts, and the ground
          (Sorry no fancy diagram)
           Put your foot up against the jack, and then bang the nut loose.
           Be careful.     
          If anybody understands what Im trying to say, feel free to make
          one of those nifty diagrams out of slashes and periods and what not
           to help illustrate it.
   Oh yeah, if this doesnt work, take it to a garage, hand the guy the 46mm
   socket, and ask him to impact it off.  If you look sorry enough he'll do
it for free!