What was found
LEFT CONTROL YOKE INPUTS BEYOND 30O YOKE BECOMES STIFF AND IF RELEASED AT MORE THAN 30O, LEFT YOKE WILL STAY AT THAT POSITION UNTIL MANUALLY RETURNED TO ZERO. PROBLEM DID NOT OCCUR BELOW 10,000 FT ON CLIMB OR DECENT. REPLACED AILERON QUADRANT CENTERING SPRINGS. REPLACED CAPTAINS CONTROL YOKE GEAR ASSY, OPERATIONAL CHECK PER MM 27-00-11, OK.