Thanks for the comments guys, a little more info first...
I polished up all the ring terminals on the wires that I disconnected from the brush leads. Cleaned the brass rings with some plastic safe electrical contact cleaner and a soft brush, and re installed the brushes. I then cut some long strips of 400 grit emery paper and inserted it between the brass rings and the brushes. I pulled the paper through, grit side to the brushes, following the normal direction of rotation.
I picked up a couple of #10 - 24 brass nuts to replace the rusty ones on the brush connectors and reconnected everything.
Fired it up and it works.
