As reported to the FAA. Reports are unverified, and codes are left as the FAA publishes them.
What was found
DURING LUBRICATION OF A MAIN ROTOR HUB, WE DISCOVERED THAT THE SPRING IN THE GREASE FITTING (NAS516-1A) WAS PRESSED OUT FROM THE FITTING AND BLOCKED THE GREASE PASSAGE. THIS HAPPENED (3) TIMES. WE FOUND THE SPRINGS AFTER EVERY ATTEMPT. THIS COULD RESULT IN A LOOSE SPRING IN A ROTATING BEARING. (K)