It might depend on your machine but access is usually from the rear - here's a video about replacing the carbon brushes on a WM motor - will be mainly similar to yours...
http://www.youtube.com/watch?v=HELgV4KOsT0
Brushes are relatively easy to change and don't cost much - I hope it's a good diagnosis...
Good luck...
Peccavi, June 2009
