1957 Mercedes-Benz 300 Adenauer Sedan The W186 Model 300 was a four-door luxury sedan produced by Mercedes-Benz between 1951 and 1957. It was the company's flagship model at the time, succeeding the World War II era W150. Three versions were produced in succession, known informally as the 300a (or simply 300), 300b, and 300c. An enlarged "300d" variant built on the W189 chassis succeeded it in late 1957. Also referred to as a "Type 300", the W186 was equal in features and price but superior in p