There has been a couple of discussions about tapered axles, replacement of complete differentials and such. This may have been covered but here is a very good article describing how to convert from a tapered hub / brake drum unit to a standard brake drum. Much easier to service and less expensive.
This is also a good time to change over to standard studs if you are still running the left handed studs on the left side.
http://hotrodsandhemis.com/PolaraRearBrakes/TaperedAxleBrakes.htmlDennis C.