On October 20, 2002, about 1120 eastern daylight time, a Piper PA-32-300, N56655, piloted by a private pilot, sustained substantial damage when it went off the right side of the runway and struck a part of the visual approach slope indicator (VASI) system. The airplane was landing on runway 36 (2,556 feet by 75 feet, asphalt), at the Canton-Plymouth Mettetal Airport (1D2), Plymouth, Michigan. when the accident occurred. The 14 CFR Part 91 personal flight was operating in visual meteorological conditions. The pilot and passenger were not injured. The flight departed Paul C. Miller - Sparta Airport (8D4), Sparta, Michigan, at 1030. The pilot reported that upon landing on runway 36, the winds were 270 at 8 knots. He stated that upon touching down he realized he was moving a little fast; the airplane didn't settle and seemed to float. He applied braking to slow down but the right brake was not working. The pilot attempted to slow the airplane by using left braking and right rudder. The pilot reported that the aircraft then veered to the right (east side) and went off the runway. The pilot noted that he attempted to bring the airplane back onto the runway. The aircraft subsequently struck the VASI system with the left wing and the airplane caught fire. The pilot and his passenger safely exited the aircraft and the fire was put out by the pilot and airport staff. The pilot made a flight the day prior to the accident and reported that the brakes were working fine. The pilot stated "Had I known the brake fluid was low again, and that I did not have complete brake function, I wouldn't have made the flight." He reported that he had maintenance performed on the brakes on August 8th and September 25th of 2003, at which time the mechanic bled the lines and added fluid. The pilot reported that, subsequent to the accident, a seal within the brake master cylinder was found to be defective. He reported that this allowed the fluid level to be low and air to enter the brake lines.