What was found
AFTER RETURNING FROM A FLIGHT, GROUND CREW NOTICED HYDRAULIC FLUID ON BOTTOM OF NR 1 PYLON. INVESTIGATION REVEALED THE HYDRAULIC SUPPLY AND PRESSURE LINES WERE CHAFING. BOTH LINES WERE CHAFED EVENLY, BUT THE PRESSURE LINE JUST STARTED TO LEAK. THE LINES WERE RUBBING AT APPROXIMATELY 3 INCHES FORWARD OF THE AFT BEND WHERE IT COMES OUT OF THE FUSELAGE AND STARTS TO GO FORWARD THROUGH THE PYLON. NOTHING WAS OUT OF PLACE INCLUDING THE LINE CLAMPS. INSPECTION OF THE RIGHT PYLON REVEALED GOOD CLEARANCE. INSTALLATION OF THE NEW LINES IN THE NR 1 PYLON RENDERED GOOD CLEARANCE.