Hmmm.. Removing the motor will most likely cause you other problems... e.g.if you don't can the belt tension right wehen you put it back, the belt will eather slip or put additional load on the drum (and motor) bearings which will lead to a very costly repair (or trip to the hole in the ground otherwise known as the landfill site).
Most motors that have replaceable brushes can have them changed in situ and either clip in and out or are retained by a single screw on each brush. It can be a little fiddly but it's worth the perseverence.
Pete.
December 2004