I've never worked on one of these machines, but this might help.
Disconnect all electrical supply to the machine. Remove the motor, for easy access to the brushes.
There should be a clip, pin, spring or nut, screw or bolt holding the brushes in, remove and only work on one side at a time.
On some motors is is necessary to dismantle the motor to replace brushes. This involves stripping the bearings and armature and associated parts from it. Best left to an expert.
Hope this helps.
Ross.
Ross, December 2012
