The 300, 300b, 300c (chassis code 186), and successor 300d (chassis code 189) models were touring cars, often referred to as Adenauers after Konrad Adenauer, the first Chancellor of the Federal Republic of Germany. In office from 1949 to 1963, he employed six custom convertible, hardtop, and landaulet versions during his tenure.
These large saloons and four-door cabriolets featured many luxury features. Options such as Becker radio, VHF mobile telephone, and dictation machine were geared to the business man and politician. Among the custom features in Chancellor Adenauer's "parade cars" were writing desks, sirens, curtains, dividing partitions, sunroofs, and half-roof landaulet configurations.
The 300s and its successor the 300Sc (chassis code 188) were all but handmade sports tourers, the pinnacles of the Mercedes line of their era. Each were available in 2+2 coupe, cabriolet, and roadster versions.
300 (W186 II)
The "W186" Type 300, introduced in November 1951, featured graceful modernist bodywork atop Mercedes proven X-frame chassis. An all new 3 L (2996 cc/182 in³) overhead cam, aluminum head straight-6 was coupled to a 4-speed all-synchromesh manual gearbox. Twin downdraft Solex carburetors made possible by an unusual diagonal head-to-block joint exploited oversized valves to produce 115 PS (85 kW; 113 hp).
Designed to give reliable service under prolonged hard use, the engine featured deep water jackets, thermostatically controlled oil cooling, copper-lead bearings and a hardened crankshaft. With no natural cruising speed, the car could sustain anything up to its maximum speed all day, road conditions permitting.
The four door, six passenger Type 300 was available both as a saloon or cabriolet (officially called Cabriolet D). A central lubrication system was fitted, along with an innovative dsahboard-operated rear load-levelling suspension that increased stiffness by one-third.
The 300's frame was made of ovoid steel tubes, with a double wishbone, coil spring axle and stabilizer bar up front and Mercedes` typical double coil spring rear swing axle. Brakes were hyrdaulic drum all around, steering worm-and-sector, replaced in 1952 by a recirculating ball unit.
6,214 saloon models and 591 Cabriolet Ds were produced until September, 1955 (including the 300b).
300b (W186 III)
March 1954 saw power brakes introduced via a remote vacuum tank with the Type 300b. Vent windows were also introduced for the front windows. Power of the engine was upped to 125 PS (92 kW; 123 hp) via different Solex carburettors and a higher compression ratio (7.5:1 instead of 6.4:1).
300c (W186 IV)
A larger rear window was added in September, 1955 on the Type 300c. An automatic transmission was also introduced for the first time. This car was priced at $10,864 in the United States (DM 22,000 on the home market), with the convertible commanding a pricy $14,231 (DM 24,700). The c also featured a swing axle rear independent suspension.
A special Innenlenker model (also called the Type 300 Lang) limousine model rode on a 20 cm (7.9 in) longer wheelbase and became available from July, 1956 (price: DM 25,000).
While the Cabriolet D was cancelled after June, 1956 (51 built), the saloon remained in production until July, 1957 and was built in 1,432 units.
The "W188" Type 300 S was Mercedes-Benz's top-end vehicle on its introduction at the Paris Salon in October 1951. The Type 300 S came as a 2+2 coupe, cabriolet (with landau bars) (officially Cabriolet A), or roadster. Although mechanically similar to the contemporary W186, the largely hand-built W188 was marketed as one of the top luxury cars in the world.
7.8:1 compression and triple Solex carburettors raised engine output to 150 PS (110 kW; 150 hp) at 5000 rpm.
From July, 1952 to August, 1955, a total of 216 Coupés, 203 Cabriolet As and 141 Roadsters were produced.
1955 saw the substitution of Mercedes-Benz's "low-pivot" independent suspension in the rear, and the addition of fuel injection in the Type 300 Sc whose inline-six now delivered 175 PS (129 kW; 173 hp) at 5400 rpm. Visually, a pair of chrome strips on either side of the hood denotes this "Sc" model.
Prices rose to DM 36,500 and 98 Coupés, 49 Cabriolet As and 53 Roadsters were built until April 1958.
Introduced in August 1957, the 300d was the linear successor to the 300c, with a longer wheelbase, fuel injection, and unique hardtop configuration transforming it into a pillarless phaeton.
The additional 4 inches of wheelbase provided greater rear legroom and established the car as a true limousine in direct competition with the Rolls-Royce Silver Cloud. Removable rear quarter lights allowed an unobstructed view in and out from the front vent window on back, much valued in the model's popular role as "parade car".
Employing a slightly detuned version of the 300 SL sports car's Bosch fuel injected engine, the 300d produced 180 PS (130 kW; 180 hp) at 5500 rpm Automatic transmission was standard. Power brakes, power steering, and Artic-Kar air-conditioning were added as an options.
A total of 3,077 300d models (priced at DM 27,000) was produced through March 1962, along with 65 special-order 300d-based Cabriolet Ds (DM 35,500). After some initial overlap with the smaller, more contemporary styled W112 chassied 300SE, the 300d was ultimately replaced as M-B flagship by the 600 pullman "Grand Mercedes".