On July 1, 2014, about 1455 central daylight time, a Beech A36 airplane, N136EL, sustained substantial damage during and intentional wheels-up landing to runway 12L at the San Antonio International Airport (SAT). The pilot and 3 passengers were not injured. The airplane sustained substantial damage to the fuselage. The aircraft was registered to Angel Brothers Aviation Ltd., and operated by the pilot under the provisions of 14 Code of Federal Regulations Part 91 as personal flight. Visual meteorological conditions prevailed for the flight, which operated on a visual flight rules flight plan. The flight originated from Baytown Airport (HPY), Baytown, Texas, at an unconfirmed time. In a telephone interview with the pilot, he stated that upon extending the landing gear he did not get a gear-down indication for the left main landing gear. He stated that the right and nose landing gear lights indicated extended. The pilot made several unsuccessful attempts to extend the landing gear. He had advised the SAT air traffic controller of the problem and elected to land the airplane with the landing gear in the retracted position. Examination of the airplane revealed that the left main landing gear retract rod had fractured and buckled near the landing gear extension motor. Examination of the retract rod confirmed that the rod eye at the end that attached to the gear motor had fractured. The bearing remained attached to the gear motor arm. The retract rod was constructed from a steel tube with a link fabricated at the end that attached to the motor. The link was composed of two formed steel plates riveted together and welded to the end of the tube. The fabricated link was bent about 90 degrees in two places. The first bend was through the eye that held the bearing, and the second bend was about five inches farther outboard. The bends were in opposite directions forming a "Z" shape. Two of the three rivets that connected the link plates together were not found. The third rivet, the farthest outboard, was intact. The steel tube was bent about 5 degrees, 20 inches from the inboard end. Examination of the remainder of the landing gear components revealed no anomalies. The only preimpact damage that was evident was the damage to the landing gear retract rod.