found a useful link for you
http://www.peachparts.com/shopforum/showthread.php?threadid=5900&highlight=alternator+carbon+brush
You may not be able to get the exact rebuilt kit for these alternators. so once you have the carbon brushes out go to the Ace or other similar guys and get a closest matching one then fileit to the same shape. I have not done this so cant tell you more but look under blower motor carbon brush replace and you will find some nice posts.
MVK