What was found
AFTER TAKEOFF, "NR 2 HYD LOW PRESS" CAUTION MESSAGE WAS DISPLAYED. THE AIRCRAFT RETURNED TO THE ORIGINATING AIRPORT AND PERFORMED AN EMERGENCY LANDING. MAINTENANCE FOUND THE FORWARD NR 2 BRAKE ACCUMULATOR CONNECTING HYDRAULIC LINE'S NUT LOOSE (CRJ700/900 IPC 29-17-06, FIG.23-AA1, ITEM NR 90). THE NUT WAS RE-TORQUED AS PER STANDARD PRACTICES AND NR 2 ENGINE DRIVEN PUMP (P/N 66190-3, S/N K0651) WAS REPLACED AS A PRECAUTION. NR 2 HYDRAULIC SYSTEM WAS SERVICED AND AIRCRAFT RETURNED TO SERVICE. NO MAINTENANCE HAS BEEN PREVIOUSLY PERFORMED ON THE HYDRAULIC LINE, NEITHER ON NR 2 BRAKE ACCUMULATOR. AIRFRAME HOURS WERE: 2625:04 AND CYCLES WERE: 1280.