Early models were equipped with rubber Rear Spring Isolators, which are prone to collapse with age. Later cars were built with solid metal Isolators not subject to collapse. It is a relatively easy job to convert those cars still fitted with rubber Isolators to the later solid type. Applicable chassis ranges (cars not originally fitted with solid Isolators):
Countries other than USA: chassis numbers 01001-16213.
USA model cars: chassis numbers 01001-15555.
