The pilot reported that he was positioning for a pickup of passengers and he had completed a visual circuit and approach to the strip. He achieved a gentle touchdown within 100 metres of the threshold of the 1065 metre strip on both main wheels. Coincident with lowering the nosewheel onto the strip, the pilot reported feeling the aircraft lurch which he first took to be symptomatic of a flat tyre on the left maingear. He had no trouble maintaining directional control. A little later, the left wing dropped further and the gear warning horn sounded. The pilot was able to keep the aircraft within the defined width of the strip and, on coming to rest, he shut down the aircraft before egressing. A post flight inspection by the pilot showed that the left maingear oleo leg had swung rearwards and the lower surface of the flaps had been dented by the tyre. The reduced ground clearance had allowed the left propeller to strike the ground but the left maingear doors were out of contact with the ground. A detailed inspection of the maingear components showed that the left maingear drag link centre bolt had failed in fatigue. Furthermore, all the landing gear components showed signs of wear beyond tolerances and this condition was evident of inadequate maintenance and inspection.