What was found
DURING REMOVAL OF NO TAIL ROTOR (NOTAR) FAN BEARING, DISCOVERED THE FAN PITCH SLIDER, P/N 500N5367-3, AND FAN SUPPORT SHAFT, P/N 500N5357-11, HAD PITTING CORROSION. A NEW SUPPORT SHAFT AND SLIDER WERE INSTALLED. WITH NEW PARTS INSTALLED, A CONDITION OF EXCESSIVE BINDING OF THE FAN PITCH SLIDER EXISTED. IN CONJUNCTION WITH MD HELICOPTERS TECH REPS, DETERMINED THE TORQUE APPLIED TO THE PITCH SUPPORT SHAFT LOCKNUT P/N NAS1493-6F (60 TO 70 FEET/POUNDS AS SPECIFICIED IN THE HANDBOOK OF MAINTENANCE INSTRUCTIONS) WAS EXCESSIVE AND WAS THE MAJOR CONTRIBUTING FACTOR OF THE BINDING OF THE PITCH SLIDER. (X)