On June 9, 2000, about 1445 Alaska daylight time, a wheel equipped Piper PA-18-150 airplane, N9739P, sustained substantial damage during a forced landing at an off airport site located about 35 miles northwest of Skwentna, Alaska, at 62 degrees, 17 minutes north latitude, 151 degrees, 51 minutes west longitude. The solo certificated private pilot was not injured. The airplane was being operated as a visual flight rules (VFR) personal flight under Title 14, CFR Part 91, when the accident occurred. Visual meteorological conditions prevailed, and no flight plan was filed. The flight originated at Hilltop Airstrip, Chugiak, Alaska, about 1230. During a telephone conversation with the National Transportation Safety Board investigator-in-charge on June 9, the pilot reported that while in cruise flight, about 200 feet above the ground, all engine power was lost. He said that the fuel selector valve was on the right fuel tank and that he intended to "run the right tank dry," then switch tanks. As the engine began to lose power, he switched the selector to the left fuel tank, but engine power was not immediately restored, and he selected a forced landing area on a sandy river bank. He added that during the landing roll, without applying the brakes, the airplane slowly nosed over. The airplane sustained substantial damage to the left wing lift strut, and rudder. The pilot stated that just prior to the accident flight he added hydraulic brake fluid to the brake system. The pilot submitted a written report to the NTSB dated June 23. In his written report, the pilot indicated that a postaccident inspection revealed that the main wheels would not rotate. He wrote that as he bled the hydraulic brake system, both air and pressurized hydraulic fluid escaped from the bleed valve. After bleeding the hydraulic system, both wheels operated normally.