I looked in to this before deciding to buy a couple of bearings for for my '41-'46 box. Go about 1/2 way down the page to the one piece bearing replacement. Looks like '41-'59 use the same bearing, which is the same as the tractor bearing here,
http://davistractor.com/ushop/index.cgi?ID=PWO5I0&task=show&cat=MF%2dSteering+%26+Front+Axle
How about this from the Filling Station
http://www.parts123.com/parts123/yb.dll?parta~dyndetail~Z5Z5Z50000014a~Z5Z5Z58359~P17.50~~~~S2PJ14RE1E69151511224M~Z5Z5Z5~Z5Z5Z50000014x
