Don't know. One is really shiny and the other is carbony like it wasn't
making contact. You tell me? Is one enough to keep the alt running? The
shiny one is about 3mm above the housing, and the dark one is about
2mm.

Any tips for how to get the screws back in with the brush assy with one
hand in an obscure awkward position? I'll try tape. Magnetic
screwdriver? Glue?