What was found
DURING DEPARTURE CLIMB AFTER GEAR RETRACTION, HYDRAULIC SYSTEM 'B' QUANTITY DECREASED TO ZERO AND LOW PRESSURE INDICATION ILLUMINATED. FLIGHT DUMPED 6,000 LBS OF FUEL AND INITIATED RETURN TO MIA. ON APPROACH THE 'A' SYSTEM HYDRAULIC QUANTITY DECREASED TO 1.9 GALLONS ALTHOUGH PRESSURE REMAINED IN GREEN BAND. AIRCRAFT LANDED WITHOUT FURTHER INCIDENT. MAINTENANCE FOUND HYDRAULIC LEAK AT RIGHT ELEVATOR POWER CONTROL UNIT. REPLACED ELEVATOR PCU AND 'B' SYSTEM PUMPS AND FILTERS. LEAK AND OPERATIONAL CHECK NORMAL.