[bobbader]

While your friend's starter spins like 12 Volt, you haven't mentioned if it solved the hard starting problem when the engine is warm. If it did, that's great and YES, your starter needs some attention. As to whether you can give it the attention it needs yourself ?????????? Just as most responders pointed out that your cables might be the cause of "hard starting while warm", your starter may have more issues than cleaning the commutator and replacing brushes. I assume your $220 rebuild is from a reputable auto electric rebuilding shop (or Model A parts supplier). In either case, a reputable rebuilder will do the job. This should involve testing of components before the installation of new parts. These tests are crucial to the success of the rebuild. The armature and commutator are tested on a "growler" for shorts, breaks in continuity, etc. If you don't have access to such a tool & knowledge of how to use it (or any test equipment that might be used instead of a growler), it's time for a professional to take over. Field windings can be tested with a good ohmmeter. Even that requires knowing how to test for problems that might occur under load. If these components check out OK, the rebuilder needs to know what else to check that might cause the poor starting when warm scenario. If your capabilities and tool supply meet these criteria, go for it. If not, the $220 is probably money well spent.

Good luck. Bob Bader