As reported to the FAA. Reports are unverified, and codes are left as the FAA publishes them.
What was found
ORD - INFLIGHT SFO-JFK. CREW REPORTED CENTER HYDRAULIC FLUID LOSS IN FLIGHT. FLIGHT DIVERTED ORD LANDED WITHOUT INCIDENT. AIRCRAFT REMOVED FROM SERVICE. FOUND O-RING PROTRUDING FROM FITTING ON HYDRAULIC PRESSURE MODULE. REPLACED O-RING. SYSTEM GROUND CHECKED NORMAL OPERATION.