What was found
AFTER TAKEOFF, WITH LG RETRACTED, OBSERVED HYDRAULIC SYSTEM NR 4 LOOSE WITH BOTH NR 4 EDP, ADR LOW PRESSURE ON. AOM 2-2-55 AND 2-2-59 FOLLOWED, RETURNED TO DEPARTURE.FOUND LT WING GEAR DOOR ACTUATOR HYDRAULIC LINE WORN. REMOVED AND REPLACED HYDRAULIC LINE, AND REWORKED NR 4 EDP IAW MM 29-11-05, INSTALLING EDP DISPATCH KIT IAW MM29-11-03, SERVICE, AND LEAK CHECK OK. EDP PLACED ON MEL IAW MEL 29-1. AIRCRAFT RETURNED TO SERVICE.