Replaced rear bearing with kit which came with new shaft, bearing,washer(spacer) foam seals and front plastic supports.The possible cause of your scrapping drum is the washer (spacer) is left out causing drum to sit too near the rear metalwork or perhaps the fan (mounted on the motor shaft) is catching on the rear cover.I found that the fan blades do bend very easily and can catch. If the front plastic supports are worn this will allow the drum to run on the metalwork.Did you replace these?
Chris
September 2010