Sugarmel
If you know how to do this
http://www.zeckhausen.com/E39_Bearings.htm
It should be easy to replace the rear bearings .....I did both and the back was much easier than the front....the difference? you need a tool to free the hub from the rear axle shaft.....
Sorry I don't have step by step directions for rear bearing removal.....hope the above link helps.
regards
billb