There's a video on Youtube showing brush change in a W/M
http://www.youtube.com/watch?v=0GmtRBiXLFc
On my Bosch machine the brush holders are held in place with two cross point screws - flying push on lead.
You can get them from a local supplier or on line
Yellow Pages / Google
Carbonbrush.co.uk might have what you need but I think perhaps not - mostly tools
Good luck...
Peccavi, November 2009