Replacing the bearing components inside one of these machines is a task even experienced zanussi engineers wish to avoid. Done properly by yourself the parts you will need are a rear drum, (possibly a drum front if it's got that bad), inner drum, a drum seal, and I always replace the element. additionally you may want to include a couple of band-aids.
Not replacing all components will probably result in the same problem in a couple of months time.
retail parts cost at well over £100, I'd take a trip to Comet.
Paul
August 2004