What was found
DURING CLIMBOUT FROM EWR AT 25,000 FT CREW NOTICED A RAPID LOSS OF HYDRAULIC SYSTEM-A FLUID FOLLOWED PROPER CHECKLISTS AND RETURNED TO BASE. EVENTUALLY LOST ALL SYSTEM-A FLUID. FOUND HYDRAULIC FLUID POURING OUT OF CASE DRAIN OVERFLOW LINE FROM FLAP DRIVE MOTOR IN RT WHEEL WELL. REMOVED FLAP DRIVE MOTOR. REPLACED RT HYDRAULIC FLAP DRIVE MOTOR IAW M/M 27-51-062-4, OPS CHECKS GOOD. BECAUSE OF WRITE-UP, ALSO REPLACED BOTH NR 1 AND 2 ENGINE CASE DRAIN FILTERS IAW M/M 29-11-041-2. THERE WAS NO CONTAMINATION FOUND IN OLD FILTERS.