What was found
PHX - NOSE WHEEL STEERING FAILURE - FLT 0716 - AFTER NORMAL LANDING AT PHX EN ROUTE FROM LAS NOSE WHEEL STEERING FAILED ON TAXIWAY, AND L/H HYDRAULIC QUANTITY DECREASED TO ZERO WITH SYSTEM PRESSURE LIGHT ILLUMINATED. EICAS MESSAGE FOR L/H HYDRAULIC SYSTEM DISPLAYED. AIRCRAFT REQUIRED TOW TO GATE. MAINTENANCE FOUND L/H LANDING GEAR DOWN LOCK ACTUATOR FLEX LINE RUPTURED. REMOVED AND REPLACED L/H LANDING GEAR DOWN LOCK ACTUATOR FLEX LINE; LEAK CHECK COMPLIED WITH IAW BMM 32-32-02, PG. 407, STEP 11 & 12.