What was found
(CAN) FLIGHT CREW REPORTS ON TAXI OUT OF YVR AIRCRAFT LOST 'A' SYSTEM HYDRAULICS AND NR 1 'A' PUMP LOW PRESSURE WARNING LIGHT ILLUMINATED. AIRCRAFT RETURNED TO GATE UNDER ITS OWN POWER. MAINTENANCE INSPECTION REVEALED THE NR 8 GROUND SPOILER ACTUATOR PISTON HAD POPPED OUT OF HOUSING AND THE CASING WAS ENTIRELY CRACKED AROUND THE HOUSING. COMPONENT WAS REPLACED AND SYSTEM GROUND CHECKED SERVICEABLE. AIRCRAFT RETURNED TO SERVICE WITH NO FURTHER INCIDENTS TO REPORT.