The Mercedes-Benz 300 was launched at the 1951 Frankfurt Motor Show, with chassis code W186. In the immediate postwar years, economic conditions forced the company to mostly limit production to the entry-level four-cylinder 170 V model, but by the 1950s Mercedes was ready to build extravagant, exclusive luxury cars again.

The 300 series was designed to compete with Rolls-Royce quality. It was complex, expensive and luxurious, and offered as a huge sedan with optional division windows or as a four-door cabriolet. The 300 was powered by a 115-bhp 3.0-liter six-cylinder engine coupled to a four-speed synchromesh gearbox, and was capable of cruising at 100 mph. The X-frame was built of oval tubes, the front suspension was independent by coil springs and wishbones, and the rear featured Mercedes-Benz’s swing axle. The rear suspension was adjustable at the dashboard and a central lubrication system was foot-operated.

The 300 was indelibly associated with West Germany’s first postwar Chancellor, Konrad Adenauer, who held office from 1949-63. He had six custom-built “Adenauer” 300s during his term in sedan, cabriolet and landaulet configurations. They had writing desks, VHF radios, sirens, division windows, curtains and sunroofs, while the rear landaulet roof could be folded down for parades.

The big Mercedes was favored by executives, and 6,214 sedans and 591 cabriolets were built in the 300 and 300b series from 1951-54. The 300b gained power brakes and front vent windows while power was boosted to 125 bhp through bigger Solex carburetors and by raising the compression ratio to 7.5:1. The 300c of 1955-56 carried a larger rear window, and an automatic transmission was optional. A total of 1,432 sedans were built along with a mere 51 cabriolets.

For 1957 the W189 300d was modified with taller rear fenders with vertical lights, and featured a pillarless roof, which created an American style hardtop when all the windows were lowered. The big new was under the hood, where Bosch fuel injection was fitted, increasing power to 160 bhp. The restyling was popular and the 300d was built until 1962, with sedan sales increasing to 3,077 units, though cabriolets remained rare, and only 65 were sold.