As reported to the FAA. Reports are unverified, and codes are left as the FAA publishes them.
What was found
AFTER INSTALLING NEW FUEL DRAIN, WAS UNABLE TO OPEN DRAIN. THE SHAFT IN AREA JUST BELOW SEALS SEEMS TO BIND ON HOUSING. THIS IS EVIDENT BY USING A MAGNIFYING GLASS AND LOOKING AT THIS AREA. THIS IS THE NEWER VALVE (WITH THE HEAVIER HEAD ABOVE THE SEAL.