On July 2, 2003, at 1000 eastern daylight time, a Cessna 140, N89360, piloted by a private pilot, sustained substantial damage when the left main landing gear axle separated from the landing gear during landing on runway 18 (3,502 feet by 75 feet, asphalt) at the Mason County Airport (LDM), Ludington, Michigan. The 14 CFR Part 91 personal flight was operating in visual meteorological conditions without a flight plan. The pilot reported no injuries. The flight originated from the Manistee County-Blacker Airport, Manistee, Michigan, at 0930. According to the pilots written statement, during landing roll he felt a strange wobble. The pilot reported the airplanes left main gear axle separated from the landing gear strut. The pilot was able to maintain directional control using the rudder. The pilot stated the main gear leg dropped into hole in the pavement, which resulted in the airplane nosing down causing a prop strike. The pilot reported the airplane slid to a stop and rested on the propeller and cowling in a tail up position. The pilot stated that subsequent to the accident he noticed the top two bolts of the left main gear axle sheered off, which put undo load on the bottom two bolt causing them to break off. The pilot stated that the airplane had a brake assembly kit installed. The pilot reported the mechanic used bushings and smaller diameter bolts to mount the axle to the gear leg.