On August 2, 2010, about 0830 central daylight time, a Cessna 180B airplane, N5177E, was substantially damaged during landing at Burnet Municipal Airport (BMQ), Burnet, Texas. The private pilot was not injured. The airplane was owned and operated by a private individual under the provisions of 14 Code of Federal Regulations Part 91 as a personal flight. Visual meteorological conditions prevailed for the flight, which operated without a flight plan. The flight originated from the Llano Municipal Airport (AQO), Llano, Texas about 0700. The pilot reported he was delivering the airplane to BMQ to have the tailwheel examined to troubleshoot tailwheel shimmy. He performed a three point landing and during rollout the rudder pedals began to “shudder violently.” The pilot was unable to control the airplane and it exited the right side of the runway. During the runway excursion the left wing hit the ground, substantially damaging the left aileron. The tailwheel assembly was sent to a repair station by the owner and disassembled. The tailwheel compression spring (part number 3222) was found broken. Failure of the compression spring would allow the tailwheel to caster freely. The broken compression spring was not retained so an examination to determine the cause of the failure could not be performed.