As reported to the FAA. Reports are unverified, and codes are left as the FAA publishes them.
What was found
STL - INFLIGHT JFK-LAX. CREW NOTICED LEFT SYSTEM QUANTITY EICAS MESAGE AND THEN LOSS OF QUANTITY ON THE LEFT SYSTEM GAUGE. EMERGENCY DECLARED FLIGHT DIVERTED STL LANDED WITHOUT INCIDENT. AIRCRAFT REMOVED FROM SERVICE. REPLACED TWO HYDRAULIC LINES FOR RUDDER RATION CHANGER. SYSTEM GROUND CHECK NORMAL OPERATION.