Looking for a Surce of 29 Starter Brush Autolite MU-13-7b

Unknown

Began my starter rebuild. Noticed the brushes are about 1/2 worn down and thought while I'm at this point its just good practice to replace. They appear to be continuously active when the engine is running, armature is directly geared to flywheel with no bendix type disconnect.

Wasn't able to locate a source either local car parts stores or on Ebay or web. The number on the brush is Autolite-13-7b.

Any sources or substitutes out there?



Thanks

Jack