Thanks for the info.Hi,
Prestolite motor MTC-4001 uses (8) brushes part #MGP-12*. "*" would be replaced with letter designation for the grade. I forget that but recall they are grade H100 by Morganite. The size is .997×.548×~1-3/8"long. Service replacement part number may be different. Forklift parts/repair places should have suitable brushes because size was used on so many forktrucks. eBay sometimes has them.
Unusual they would wear out from normal use. What's the application?