What was found
CREW ON TAXI CHECKING FLIGHT CONTROL MOVEMENT NOTICED A RESTRICTION IN RUDDER MOVEMENT. THE RUDDER WAS LIMITED TO APPROXIMATELY HALF TRAVEL TO THE LEFT AND A LOUD CLUNKING NOISE WAS HEARD WITH THE APPLICATION OF RIGHT RUDDER PEDAL. THE NOISE SEEMED TO BE COMING FROM UNDER THE FORWARD LAVATORY FLOOR. THE AIRCRAFT RETURNED TO DFJC MAINTENANCE AREA FOR AN INVESTIGATION, FOUND FORWARD LAVATORY DRAIN CABLE RESTING AGAINST TORQUE TUBE FOR RUDDER RESTRICTING FULL MOVEMENT.