What was found
FLIGHT CREW REPORTED THAT ON TAXI OUT AND PRIOR TO TAKING THE ACTIVE RUNWAY, A MIST AND HYDRAULIC FUMES WERE NOTED IN THE CABIN FOLLOWED BY A HYDRAULIC FAILURE. THE FLIGHT CREW DEPLOYED ALL OF THE EVACUATION SLIDES AND EVACUATED THE AIRCRAFT. AIRCRAFT GROUNDED. THE AIRCRAFT WAS REMOVED FROM SERVICE AND MAINTENANCE FOUND THE GREEN HYDRAULIC SYSTEM BRAKE PRESSURE LINE CHAFED WHICH WAS REPLACED IAW AMM 20-23-11. A SATISFACTORY LEAK AND OPERATIONAL CHECK WAS ACCOMPLISHED