I also just replaced mine. I found the new ones at a local parts store run by an "old-timer" who actually seems to know something about parts for a '55.
There is some effort needed to replace them. On my '55, I had to remove the differential cover and then remove the parts that hold in the axles (refer to a shop manual). After removing the axles, the bearings and seals are supposed to be removed with a puller, which is a tool with a slide hammer. Since I didn't have one, I used 2 sections of 1/2 inch pipe, one 4 feet and one 2 feet. These pipes were connected together and slid into one side of the rear housing, through to the other side. I had my daughter pound on the end of the pipe with a hammer while I held the other end of the pipe against the inside of the bearing on the other side (used a long screwdriver inserted into the end of the pipe to hold it against the bearing). I stuck a rag between the end of the pipe and the bearing to cushion the blows. Anyway, this worked. Putting it all back in is a lot easier.
