I did one a while back (forget the make of machine) because the seal had split.
It was a ****** of a job.
the hard bit was the band that held the seal to the drum. Think along the lines of an over sized jubille clip, made of stainless steel, with razor sharp edges, stuck down between a small gap between the drum and the front casing. almost impossible access, and you need three hands, a looong screwdriver and the patience of a saint.
If it was just a bit dirty I wouldn't bother.