On July 21, 2017, about 1100 central daylight time, a Stinson 108 airplane, N8954K, departed the runway surface while landing at the Lee's Summit Municipal Airport (KLXT), Lee's Summit, Missouri. The pilot and passenger were not injured, and the airplane was substantially damaged during the landing. The airplane was registered to and operated by a private individual under the provisions of 14 Code of Federal Regulations Part 91 as a cross-country flight. Visual meteorological conditions prevailed at the time. The local flight departed Newton, Kansas, about 0900. The pilot reported that he planned to stop at KLXT to refuel and elected to land on runway 29. After touchdown, the airplane started to drift left, so he applied the right brake and rudder; however, the brake "went to the floor." The pilot was unable to correct the turn and the airplane continued off the edge of the runway. The airplane came to rest in an up-right position. An examination of the airplane by the responding Federal Aviation Administration (FAA) inspector noted that the propeller was bent, the airplane's right landing gear had collapsed, and there was substantial damage to the wing spar and fuselage. The examination also confirmed that the right brake was not functional. The exam noted that the brake system malfunction was likely due to a failure of a seal