On April 6, 1997, at 1255 hours Pacific daylight time, a Piper PA-34-200T, N8188X, was substantially damaged when the aircraft went off the end of runway 13 during landing at the Healdsburg, California, airport. The private pilot and one passenger were not injured. Visual meteorological conditions prevailed for the personal flight which departed from Red Bluff, California, at 1220. The pilot reported that the flight was normal through landing touchdown. When he applied the wheel brakes after landing, both pedals went all the way down. By "pumping" the brakes he was able to get some braking action from the right brake. It became apparent to him that he would not be able to stop the aircraft on the 2,700-foot-long runway, and there was insufficient runway remaining to go-around. He permitted the aircraft to veer to the right, off the runway, and ground loop in the run-up area. He said that in the two previous landings that morning the brakes functioned properly. The reason for the brake failure was not determined.