On August 1, 2018, about 1215 mountain daylight time, a Champion 7GCBC, N57477, veered off the runway and collided with a fence during the landing roll at the Big Creek Airport (U60), Big Creek, Idaho. The airline transport pilot and passenger were not injured. The airplane sustained substantial damage to the right wing struts. The airplane was owned and operated by the pilot under the provisions of Title 14 Code of Federal Regulation Part 91. Visual meteorological conditions prevailed, and no flight plan was filed. The personal cross-country flight originated from Flying B Ranch, Cascade, Idaho at 1136 with a planned destination of Big Creek, Idaho. The pilot stated that after making a normal landing on runway 19, he applied wheel brakes. The airplane immediately turned to the left, and despite application of brakes and right rudder, the airplane veered off the left side of the runway. The airplane continued over a water sprinkler system, through a wood fence and came to rest in a stand of small trees. The pilot stated that he had never before had to brake as aggressively with this airplane. The pilot believed the brakes were malfunctioning by not applying equal brake pressure to the two brake calipers. He stated he was applying equal force to both brakes when the airplane veered left. The left brake line was breached during the accident sequence. A Federal Aviation Administration (FAA)inspector from the Boise, Idaho Flight Standards District Office monitored the replacement of the left brake line, then tested the left brake afterwards. He reported the left brake functioned normally. A visual inspection of the left brake puck revealed normal conditions. There were no indications of brake anomalies present. The airplane was loaded onto a trailer at the time of the examination therefore, no other tests of the brakes could be applied. After the airplane was removed from the trailer, the owner, with the authorization of the IIC, checked both brakes and reported normal operation. A video of the accident sequence, as viewed from inside, shows the airplane landing, veering left and coming to a stop in the stand of small trees. A witness stated that he observed the airplane make a normal landing remaining aligned with the runway centerline. He momentarily diverted his eyes and when he looked back, he noted the airplane was established in a gradual left turn, maneuvering at a slow speed in a 3-point attitude. The airplane then collided into an airport perimeter fence and came to rest about 600 ft past the touchdown point. The Champion airplane was manufactured in 1993. The tandem seat, tail dragger design was equipped with provisions for flight controls in the rear seat including rudder pedals. Brake pressure can be applied from either seat. Big Creek Airfield is an uncontrolled, public use airport. The dirt runway, 01/19, is 3,550 ft long and 110 ft wide. When landing to runway 19, there is an uphill angle of .3. Runway 19 is the recommended landing runway. The runway surface was examined and found to be in good condition with no holes or defects.