As reported to the FAA. Reports are unverified, and codes are left as the FAA publishes them.
What was found
NR 4 HYDRAULIC SYSTEM WENT FROM 8.5 GALLONS TO 2.5 GALLONS, AS PER ALTERNATE PROCEDURES DEPRESSURIZED EDP AND ADP QUANTITY STABILIZED AT 2.5 GALLONS. RETURNED TO MIA. FOUND NR 4 EDP PRESSURE LINE BULKHEAD FITTING AT VERTICAL FIREWALL DISTORTED. REMOVED AND REPLACED FITTING PER BOEING MAINTENANCE MANUAL 20-11-05. LEAK CHECK OK AT 3,000 PSI.