Installing new brushes in a generator?

["Bockisch, Paul" <Paul.Bockisch@mail.mei.com>]

  Well, here I go again with the generator questions.  I was told by a friend 
that the generator may only need new brushes installed.  If that is the case, 
then how do I do this?  What do the brushes look like anyway?  Is there a web 
site (preferably with pictures) that could answer these questions?

Thanks,
-Paul