These vehicles use a vacuum pump to supply power assist to the braking system. Due to insufficient lubrication this vacuum pump may fail. Failure of the brake vacuum pump would result in a reduction in braking power that could increase the risk of a crash. In order to correct this concern, dealers will install a locking ring in the camshaft to retain the camshaft seal disk in the proper location. This will ensure proper oiling of the vacuum pump. Note: This recall is an expansion of an earlier recall.