What was found
AIRCRAFT WAS GROUNDED: AN EMERGENCY WAS DECLARED DUE TO: DURING TAKEOFF AT APPROXIMATELY 100KTS DUE TO A VERY HARD YAW TO THE RIGHT THEN A REVERSAL TO THE LEFT. FELT LIKE WE POSSIBLY HAD A FLIGHT CONTROL ISSUE WITH THE RUDDER. FIRST OFFICER SAID THE FOOT PEDALS FELT LIKE THEY MAY HAVE GOTTEN STUCK TEMPORARILY. AIRCRAFT ABORTED TAKEOFF SAFELY AT MIA. REMOVE AND REPALCED NUMBER 1 (SMYD)-STALL MANAGEMENT YAW DAMPER MODULE (AALA202511187613), PER AMM 27-32-42. ALSO, REMOVE AND REPALCED MAIN RUDDER PCU, PER AMM 27-21-91. OPERATIONAL LEAK AND CHECK GOOD.