Thanks for the reply. Great diagram. I have the motor out of the pump assembly. LOTS of black dust (dried out seal?) Shot the windings and shaft w/brake cleaner, then immediately with bike chain spray lube. One of the brushes is about 1/3 the thickness of the other, about 1/32" thick.
I also put the voltmeter in the connector to the motor - big # one way, big negative # the other.
How much should a rebuild of ths motor cost? Can I do it myself? Or am I better off buying a new one?