Single Field Alternator Rebuild Help!

Oh man, $30-50 for a rebuilt one or $40 in parts and do it yourself? rebuilt all the way. 2 reasons: if it fails, you get another one for free, test it on their machine right out of the box. 2. Everything that wears gets tested (with the proper procedures) or replaced when they do a rebuild, and the assembly line operation just makes the time so short to do a rebuild that it gets passed along to you. I would only attempt a $3 brush replacement as most everything else seems to be good 95% of the time. I always have them test rebuilt starters after I got 3 bad ones in a row for a 351C out of the box. Seems the Ford starter is underbuilt for what it needs to do.