What was found
CREW REPORTED, IN CLIMB, NOTICED HYD PRESS FLUCTUATING ABOVE NORM. AFTER FL390, PRESS STABLE FOR 5 TO 10 MINS THEN INCREASED TO 2000 PSI AND HELD. EMERG DECLARED. A/C LANDED USING ALT GEAR EXTENSION, WITH A NO FLAPS APPROACH. PWR BRAKE FAILURE CHECKLIST USED. NO FURTHER PROBLEMS DURING LANDING. MX FOUND LOOSE WIRE SPLICE FOR NR 4 WIRE OF HYD PRESS XMITTER CANNON PLUG. NEW SPLICE INSTALLED, OPS CHECK OF HYD PRESS IND WAS PERFORMED. SPEED BRAKES, FLAPS, L/G, THRUST REVERSERS, AND BRAKE SYSTEMS WERE BLED. THE N2 BLOW DOWN BOTTLE WAS SERVICED. OP`S CHECK WAS GOOD. PROBLEM REOCCURED DURING TEST FLT LT/RT ENG DRIVEN HYD PUMPS AND RT HYD PUMP DRAIN LINE REPLACED. TEST FLT COMPLETED. A/C RETURNED TO SERV.