As reported to the FAA. Reports are unverified, and codes are left as the FAA publishes them.
What was found
MEX CREW REPORTED NLG FAILED TO RETRACT AFTER TAKEOFF. EMERGENCY DECLARED FLIGHT RETURNED MEX & LANDED WITHOUT INCIDENT. ACFT REMOVED FROM SERVICE. REPLACED LOOSE NLG STRUT AIR SERVICE VLV & DAMAGED O RING. SYS GND CHECKED NORMAL, OPERATION CLOSED.