Never seen a diagram of one but there aren't a lot of parts in them. I have replaced the brushes on them several times, you can get the brushes at most hardware stores. The magnets in them makes the reassembly the only hard part, Just getting everything lined up when assembling. For the price of a new starter and the amount of time they last I gave up repairing them. Still a nice thing to know and do a couple of times. I have found some very good starters at swap meets that just needed new brushes.