What was found
(CAN) ON SCHEDULED MAINTENANCE 1000 HRS HYD. SYSTEM 3000 PSI LEAK TEST (LANDING GEAR MM M-8101, ROUTINE MAINTENANCE) HYD. SELECTOR FOUND LEAKING TO RETURN ON GEAR DOWN SECTION. WAS UNABLE TO BUILD UP PRESSURE TO OPERATE GEAR WITH MANUAL EXTERNAL PUMP. NEW HYD. SELECTOR INSTALLED AND IT WAS FOUND LEAKING TO RETURN ON GEAR UP SELECTION. WHEN LANDING GEAR CYCLED WITH AIRCRAFT HYD.PUMP SYSTEM OPERATES NORMALLY. SUSPECT NOT TESTING HYD. SELECTOR VALVES BOTH OLD AND NEW VALVES OVERHAULED BY THEM. (TC NR 20060828003)