On August 8, 1994, at 1430 Alaska daylight time, a wheel equipped Piper PA22-150 airplane, N4450A, owned and operated by the pilot-in-command, sustained a collapsed left main landing gear and ground looped during the landing rollout at Grasser Strip on the Hula Hula River approximately 150 miles southeast of Deadhorse, Alaska. The private certificated pilot and his one passenger, the sole occupants, were not injured and the airplane was substantially damaged. The pleasure flight, conducted under 14 CFR Part 91, for the purpose of sheep hunting, last departed Deadhorse, Alaska at 1230 and the intended destination was the Grasser Strip. The pilot reported that visual meteorological conditions prevailed in the area at the time of the mishap and no flight plan was in effect. The pilot reported that the main gear broke at the point where the forward tube connected at the axle spindle and that corrosion was apparent in the area, under the fabric of the airplane. The fabric was installed in 1964. The airplane had accumulated a total time in service of 2,776 flight hours. The pilot reported that the most recent annual inspection was accomplished on June 9, 1994, 43 flight hours before the accident.