What was found
ON FLIGHT 4069 (MSP TO CLE) AFTER TAKEOFF LANDING GEAR DID NOT RETRACT, HYDRAULIC 3 PRESSURE WENT TO ZERO. THE CREW PERFORMED AN AIR RETURN BACK TO MSP FOR NR 3 HYDRAULIC SYSTEM FAILURE/LOSS OF PRESSURE. CREW DID DECLARED AN EMERGENCY AND LANDED WITH NO HYD SYSTEM 3 PRESSURE OVERWEIGHT LANDING AT 48,800 POUNDS LESS THEN 300 FPM. LANDING GEAR MANUAL EXTENSION WAS PULLED WITH GEAR IN DOWN POSITION. AIRCRAFT LANDED WITHOUT FURTHER INCIDENT. FOUND NR 3 HYDRAULIC RESERVOIR LEAKING. REMOVED AND REPLACED NR 3 HYDRAULIC RESERVOIR IAW 29-12-30. ALSO, COMPLIED WITH 05-51-34 (INSPECTION OF ACMP AFTER DRY OPERATION). REMOVED AND REPLACED CASE DRAIN FILTER. SWUNG GEAR 32-34-00. PERFORMED MANUAL EXTENSION IAW 32-34-00. ALL OPS CHECKS AND LEAK CHECKS GOOD. OVERWEIGHT LANDING FOUND TO BE ACCEPTABLE IAW 05-51-01. CASE DRAIN FILTER P/N AC7031F8.