What was found
SEA FLIGHT NR 2490: NR 1 HYD PUMP FAILED AND CAUTION LIGHT DURING CLIMB-OUT. AIRCRAFT RETURNED TO FIELD. MAINTENANCE FOUND GOOD QUANTITY LEVEL IN NR 1 HYD SYSTEM. FOUND ALL 3 DPI'S AND IN AND ON THE NR 1 HYD SYSTEM. UNABLE TO DUPLICATE PROBLEM. SUSPECT NR 1 HYD RESERVOIR LOW LIMIT SWITCH. REPLACED THE NR 1 HYD RESERVOIR AND THE RESERVOIR 225 DEG F TEMP SWITCHES IAW D8-400 MM 29-11-16-000-801 AND 29-11-16-400-801 AND 29-11-00-710-807. OPS CHECK GOOD. NO LEAKS NOTED. AIRCRAFT RETURNED TO SERVICE.