What was found
DECLARED EMERGENCY, AFTER TAKEOFF, DURING GEAR RETRACTION, HYD WARNING SYS LIGHT ILLUMINATED, HYD PRESS INDICATED ZERO. AFTER GEAR RETRACTION PRESS INDICATION RETURNED TO NORMAL. REMOVED AND REPLACED LT MLG ACTUATOR DOWN HYD LINE. REMOVED AND REPLACED HYD A-SYS ENG DRIVEN AND ELEC DRAIN CASE FILTERS, (NO DEBRIS FOUND). REMOVED AND REPLACED NR 1 ENG HYD PUMP, ALL IAW MM.