On June 1, 1997, about 1600 eastern daylight time, a Cessna 150, N22935, was substantially damaged during landing to a private grass strip in Elkton, Maryland. The certificated private pilot was not injured. Visual meteorological conditions prevailed, and no flight plan had been filed for the personal flight conducted under 14 CFR Part 91. According to the pilot, he departed on a local flight from Summit Airport, Middletown, Delaware. While over flying his farm, he decided to land on the farm's 1,600 foot grass strip. The pilot stated the wind sock was pointing straight down the runway, and he executed a soft field landing with the stall warning horn being heard intermittently. Immediately after the main gear touched down, the airplane began to veer right. The right wing struck trees, and bent upward. The airplane spun around 180 degrees, and was thrown backward. The left wing also impacted trees. The pilot reported that the right brake had grabbed after landing, which caused the airplane to veer into the trees. Examination of the brake system by a Federal Aviation Administration Inspector could not confirm that the right brake had grabbed. It was noted that 72.2 hours had elapsed since the brake discs had been replaced with new discs on October 1, 1995.