As reported to the FAA. Reports are unverified, and codes are left as the FAA publishes them.
What was found
ABOUT 30 MINUTES BEFORE LANDING IN GRI, RT HYDRAULIC ANNUNCIATOR STARTED FLICKERING, ALL OTHER INDICATIONS NORMAL. AFTER PARKING AND WHEN SETTING THE PARKING BRAKES, BOTH HYDRAULIC ANNUNCIATORS CAME ON AND HYDRAULIC PRESSURE WAS LOST. A CRIMPED TEFLON O-RING BACKING ON THE RIGHT FILTER ASSEMBLY WAS FOUND. ADVISE USE OF EXTREME CARE WHEN INSTALLING FILTER.