Just pulled this off the Maule 585 hrs total time since 2007. It looks as though the composite material that the shaft goes thru has expanded and will not allow the shaft to rotate freely. Has any body else had the problem?

Yes. I had this on my T210 several years ago. A local shop replaced the cap and adjusted and tagged it. The new cap was metal. I might still have that governor somewhere. I replaced it at overhaul with a PCU5000.