What was found
WHEN READY TO TAXI, HYDRAULIC QUANTITY GAUGE INDICATED LOSS OF FLUID, HYDRAULIC PRESSURE GAUGE INDICATED LOSS OF PRESS. ACCOMPLISHED APPROPRIATE CHECKLIST, RETURNED TO RAMP. REMOVED AND REPLACED HYDRAULIC PRESSURE LINE FROM NR 3 ENGINE HYDRAULIC PUMP, OPS CHECK AND LEAK CHECK NORMAL IAW MM 29-10-12. AIRCRAFT RETURNED TO SERVICE.