What was found
DURING THE FLIGHT CONTROL CHECK AFTER PUSHBACK THERE WAS AN AUDIBLE "CLUNK" WHILE PULLING THE YOKE TO THE AFT POSITION. AFTER RECHECKING THE FLIGHT CONTROLS THE YOKE FELT SLOW TO RESPOND TO INPUT. RETURNED TO GATE. REMOVED FROM SERVICE. C/W TECHNICAL ORDER- INSPECTION OF BOTH CONTROL COLUM DAMPENERS. FOUND EVIDENCE OF LEAKING FROM RH AND LH, HOWEVER LH NO ACTIVE DRIPS. REF W/O 370164 N/R-00001 AND N/R-00002 FOR REPLACEMENTS AND WORK PERFORMED. AFTER R+R , FREEDOM OF MOVEMENT CHECK PASSED, NO "CLUNKING" OPERATION IS SMOOTH, CONTROL COLUMNS RETURN PROPERLY. RETURNED TO SERVICE.