Several years ago the best independent parts house in town sold out to Carquest. Owner wanted to retire. He stayed on with them for a while.
I went in one day to get a GM alternator and to visit with him. He had just got in the Carquest alternator test machine and wanted to use my stuff as a test. I said sure. He checked the old alternator and sure enough, it was bad. He went in the back and got the rebuilt one off the shelf and ran it. It was bad out of the box! He got another and it was bad too! The third one had to be reclocked as it was for another application, but at least it did charge.
I had always depended on his parts being good and had never had any trouble, but after that, I started driving to the next town and visiting the best alternator rebuilder in this area!

".......So sanded it all down and resprayed. ......" Been there. done that on a couple of paint jobs over the years. Usually took me a couple of days to get over being mad before I started...
Stude M5 build