What was found
FLT#1237, BOS-DTW. (AIRCRAFT DECLARED AN EMERGENCY AND PERFORMED AN AIR TURN BACK TO BOS) ' HUD SYS 2 FAIL APPRX 45 MIN INTO FL CYAN HYD 2 LOW QTY AT 16%PRSSR AT 2900 PST OUR PRD OF 5 MIN HYD 2 QTY DROPPED TO TO 0%. PRSSR STDY AT 2900 FOR 5 MIN THEN DRP TO 2500 SLOWLY SOON APT SUDDEN DROP TO PSI; FOUND PYLON LINE ON #2 SIDE HAD PINHOLE CAUSING SYSTEM FLUID LOSS. REPLACED DAMAGED PRESSURE LINE PN:190-05170-406 BY TUBING REPAIR UNDER AMM 20-10-03-300-801-A. SEE ITEM #3387281-2 (#2 PYLON HYD LINE, CLAMPS, AND STANDOFF INSTALLED AND LEAKED CHECKED IAW AMM 29-13-00) FOR INSTALLATION OF STANDOFF, CLAMPS, AND LEAK CHECK.' (SUPPLEMENTAL ADDED TO DESCRIPTION AND DATE).