What was found
CREW REPORTED; ON APPROACH ABOVE 10,000 FT SPEEDBRAKES WERE EXTENDED & A YAWING / ROLLING MOVEMENT OF ACFT OCCURRED WITH NOSE MOVING 15-20 DEG. SPEEDBRAKES RETRACTED & CREW DISCONNECTED AUTOPILOT & PERFORMED A CONTROL CHK OF ACFT. ACFT THEN BEHAVED NORMAL. AT APPROX 4,000 FT THE SPEEDBRAKES EXTENDED, & SAME OSCILLATION OBSERVED. SPEEDBRAKES AGAIN RETRACTED & OSCILLATION CEASED. FLT CONTINUED & ACFT LANDED WITHOUT FURTHER INCIDENT. MX INSPECTED SPEEDBRAKES, & PERFORMED AN OPS CHK. OPS CHK NORMAL. A CHK FLT COMPLETED & SPEED BRAKES EXTENDED AT 200-KTS, WITH AUTOPILOT ON & IN TURNS WITH AUTOPILOT ON & OFF. NO UNUSUAL TURNS OR ROLLS NOTED. ACFT RETURNED TO SERVICE.