What was found
DURING THE TAKEOFF ROLL, PRIOR TO 80 KTS, WE HAD A SHIMMY, THE SHIMMY STARTED AT 30 KTS AND EVEN AFTER EASING THE CONTROL YOKE BACK, THE SHIMMY CONTINUED. T/O WAS ABORTED. REMOVED AND INSTALLED RENTAL NOSE LANDING GEAR ASSEMBLY. ADJUSTED NOSE STEERING SYSTEM. OPS CHECKED GOOD. LEAK CHECKED GOOD. TRAVEL CHECKED GOOD. WORK DONE IAW 750 M.M. CHAPTER 32-20-00.