As reported to the FAA. Reports are unverified, and codes are left as the FAA publishes them.
What was found
DURING ANNUAL INSPECTION FOUND THAT VACUUM SYSTEM REGULATOR FILLER WAS BLACK IN COLOR. DURING REMOVAL, FILTER DISINTEGRATED. THERE WAS NO LOG ENTRY TO INDICATE THIS FILTER WAS EVER CHANGED. IT IS IN A DIFFICULT AREA TO ACCESS AND WAS PROBABLY THE REASON IT WAS NEVER CHANGED.