I should have mentioned this before but the first thing to do is a visual inspection of the brushes to see if they are worn to a point where they don't contact the slip rings on the alternator.

If the brushes don't contact the slip rings, new brushes will probably solve the problem. If the brushes do contact the slip rings, the problem is something else and replacing the brushes will not not solve the problem. I don't remember the brushes being that hard to replace but if I remember correctly, a soldering iron is required.

Sure you could replace the alternator because it has bad brushes but that's like replacing the engine because it has bad injectors. That will work to solve the problem but it isn't the easiest or most economical solution.

P E H