On November 2, 2017, about 1400 eastern daylight time, a privately owned and operated Great Lakes Aircraft Company 2T-1A-2, N3512L, experienced a runway excursion during takeoff and nosed over at Turners Falls Airport (0B5), Montague, Massachusetts. The private pilot was not injured and the airplane, which was being operated under the provisions of 14 Code of Federal Regulations Part 91, as a personal flight, was substantially damaged. Visual meteorological conditions prevailed at the time and no flight plan was filed. The flight was originating at the time of the accident and was destined for the Orange Municipal Airport (ORE), Orange, Massachusetts.The pilot stated that he flew to 0B5 the day before the accident and assisted the mechanic with removing panels and bleeding the airplane's brakes as part of an annual inspection. He also reported that the left brake pads were replaced. He returned home that evening, then arrived at 0B5 the afternoon of the accident. After arrival he performed a preflight inspection, which included a visual inspection of the brakes, and rudder cables. He started the engine and began taxiing to the approach end of runway 16, reporting no discrepancies with the brakes while taxiing or during the run-up. He taxied onto the runway and with no wind, began the takeoff roll reporting all was normal for the first 200 ft. With the empennage off the runway, the airplane suddenly veered to the left, which he could not correct. The airplane went off the left side of the runway, down a sharp incline, then nosed over. He immediately released the restraint and exited the airplane. According to a Federal Aviation Administration inspector who examined the runway and airplane the same day, the airplane departed the left side of the runway about 425 from the approach end, and came to rest inverted in grass off the east side of the runway. Inspection of the runway revealed dark marks made by the right tire on runway centerline beginning about 350 feet from the approach edge of the runway. The marks were continuous off the east edge of the runway onto grass. Marks from the left tire were too light to capture in a photograph, while "squiggly" marks associated with the tailwheel tire began about 50 feet past the beginning of the right tire marks and continued off the east edge of the runway onto grass. The inspector reported no flat spots of either main landing gear tire. Visual inspection of the brakes while the airplane was inverted revealed both wheels rotated with no resistance. Both brakes were attached and appeared to be serviceable. The brake lines were also intact with no evidence of fluid loss. The airplane was then uprighted, which further damaged the right main landing gear, fractured the right brake line and right outer wheel half, and sheared a bolt of the brake caliper causing it to separate. Fluid was noted leaking from the right brake line when it fractured, leaving about a one-foot round stain on the pavement. Operational testing of the left brake revealed no evidence of failure or malfunction. The right brake could not be tested because of damage caused by recovery. Flight control continuity was confirmed for roll, pitch, and yaw with no evidence of binding or malfunction reported.