As reported to the FAA. Reports are unverified, and codes are left as the FAA publishes them.
What was found
AFTER GEAR RETRACTION ON TAKEOFF, NR 4 HYDRAULIC QUANTITY LOW LIGHT ILLUMINATED, AND INDICATOR WENT TO 0. CREW FOLLOWED COM PROCEDURE. DUMPED FUEL, RETURNED TO ANC, AND LANDED WITHOUT INCIDENT. ANC MAINTENANCE FOUND RIGHT CENTRAL CONTROL ACTUATOR FILTER HOUSING BROKEN. REMOVED AND REPLACED CENTRAL CONTROL ACTUATOR. OPERATIONAL CHECKED GOOD, AIRCRAFT RETURNED TO SERVICE.