300/300b/300c/300d Convertible Sedan 1951-1962 HISTORY of the 300/300b/300c/300d Convertible Sedan Two years prior to the introduction of the Mercedes-Benz "Ponton" models, the Type 300 "Adenauer" limousines were already being built by Daimler-Benz. They were different in many respects from the Ponton models, but to the casual observer, they shared a similar outward appearance. The main structural difference was that the Type 300 had a separate body and frame. These traditionally luxurious and yet technologically advanced super-cars were primarily used by governments, heads of state, royalty and other members of the heavy wallet brigade. Their engineering, luxury, high price and low production rates placed them at the very top of the already exclusive Daimler-Benz passenger vehicle hierarchy during the 1951-1962 period. The type 300 which was first introduced at the 1951 Frankfurt auto show offers an extraordinary combination of top class stability and superb riding comfort. It was the first model to recieve new styling since the end of the war. Its elegant bodywork with headlamps integrated into the front fenders sat on a cruciform chassis frame heavily boxed in at the center for extra rigidity and featuring a two-piece propeller shaft. It featured a built-in lubrication system, which the driver could operate via a pedal. This would lubricate the chassis, including the center bearing on the divided propeller-shaft. The car had independent, coil sprung front and rear suspension, with wishbones and anti-roll bar in front and swing axles in the rear. It had neither understeer nor oversteer--the tires hardly even squealed, however fast the corners were taken. A switch on the dashboard operated a servo motor which activated auxiliary torsion bars in the rear suspension, forcing the rear wheels towards a slight positive camber. This restored the car's exceptional cornering ability even when heavier loads of passengers and luggage were carried. The soft and very well damped ride had no sensation of roll, even on winding roads. Despite its size, it could stay with one on a winding road, few luxury cars rode as well. They were the first timeless Mercedes of the post-war years, and also the first designed with an eye for the American market. During its 11 year production life, this car underwent several specification changes. The 300 was succeeded in 1954 by the 300b. Externally, there were no changes; however, it had 10 more horsepower, larger brakes, higher compression, and a pair of Solex carbs. In 1955, the 300c was introduced with a first ever option for an automatic transmission. Its production stopped in June 1956. At this time, Mercedes Benz announced its cancellation of the 300's, however Mercedes Benz reinstated the 300d because of the high dealer demand for this car. The 300d had a flatter, squared-up roofline, longer rear fenders, and a slightly wider grill with a 4 inch longer wheelbase. The 300d was fuel injected instead of carburators, and the 3 speed automatic transmission was also offered. Undoubtedly the most attractive, it is also the most sought after of all the convertible sedans. Superior insulation kept noise, vibration and ride-harshness away from occupants. At 113 km/h, only the whisper of wind and tyres could be heard. The modern 6-cylinder 2996 cc engine with SOHC (single overhead camshaft) developed 114 bhp @ 4600 rpm and 145 lb-ft @ 2500 rpm. 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 term "Adenauer", as applied to the Mercedes-Benz 300 series sedan and cabriolet models produced from 1951 to 1962, is historically derived from the name, Dr. Konrad Adenauer, then chancellor of Germany, who used 6 of these 300 models during his tenure. The next 300 series, introduced in late 1954, was the "b" model, featuring upgrades of the finned brake drum, a brake booster, and front door vents. 1956 Type 300c ~ The "c" model was produced from September 1955 to June 1957, price at $10,864 US. with a convertible version at $14,231. As of September 1955, DBAG introduced the new 3-speed Borg-Warner automatic transmission built under license by Detroit Gear. The rear wheels were driven by a single-pivot swing axle. The "d" model, W189 series, produced from August 1957 until March 1962, featured engine performance, with a compression ratio of 8.55:1 went to 160HP, with the installation of Bosch fuel injection. Referred to as the hardtop limousine because all of the side windows, including frames could now be lowered. It came equipped with wide whitewall tires with a longer wheelbase, more angular rear fenders with enlarged taillights. Rear axle ratio was 1:4.67, tire size 7.60 x15, top speed 165 km/h. with 180 gross HP at 5500 rpm. Many models were produced with the Borg- Warner automatic transmission. The front and rear massive bumpers took on a different profile over preceding models. Power steering and air conditioning ("Artic-Kar") were also introduced as options. The following production numbers are exclusively the sedan convertibles and do not include the sedan models. Production Numbers: Production Numbers of the 300 and 300b from April 1951 to July 1955 1951 2 units * 1952 262 units 1953 181 units 1954 87 units 1955 59 units Total: 591 units * these were pre-production models Production Numbers of the 300c from September/December 1955 to June 1956 1955 3 units 1956 48 units Total: 51 units Production Numbers of the 300d from July 1958 to February 1962 1957 3 units 1958 23 units 1959 22 units 1960 16 units 1961 1 units Total: 65 units Buying A 300/300b/300c/300d Know what you're buying and what to look for and know what to avoid. When these cars are well maintained and properly taken care of, they increase in value. Currently for the 300; 300b and 300c values are values last updated Mar/2022 PLEASE READ THIS FIRST! A car's value is determined by condition. Standard condition guidelines are as follows: Excellent- A close to perfect original or a very well restored vehicle. Generally a body-off restoration, but a well done body-on restoration that has been fully detailed may qualify. The vehicle is stunning to look at and any flaws are trivial and not readily apparent. Everything works as new, all equipment is original, NOS or excellent quality reproductions. PLEASE KEEP IN MIND THAT # 1 CARS ARE VERY RARE, AND ARE ORIGINAL RIGHT DOWN TO THE HOSE CLAMPS. DO NOT ASSUME THAT JUST BECAUSE A CAR HAS A #1 ASKING PRICE, THAT IT IS IN # 1 CONDITION. MOST CARS FOR SALE OUT THERE ARE LOW # 2 TO HIGH # 3 CARS. Very Good- An extremely presentable vehicle showing minimal wear, or a well restored vehicle. Runs and drives smooth and tight. Needs no mechanical or cosmetic work. All areas have been detailed. Beautiful to look at but clearly not a # 1 vehicle. Good- Presentable inside and out with some signs of wear. Not detailed but clean. Body should be straight and solid with no rust-through anywhere. Shiny, attractive paint but may have evidence of minor fading or checking or other imperfections. Runs and drives well but may need some minor mechanical or cosmetic work. But it is useable and enjoyable as is. Fair- Runs and drives ok but needs work throughout the vehicle. Body shows signs of wear or previous restoration work. Any rust should be minimal and not in any structural areas. Cosmetics, body and mechanicals all need work to some degree. These values are from Collector Car Market Review and are based on actual sales of vehicles, not on asking prices of vehicles. Asking prices, and sales prices are very different. Prices last updated March 2022 300a ~ 300b ~ 300c 300d # 1 EXCELLENT $260,000.00 $430,000.00 # 2 VERY GOOD $192,000.00 $322,000.00 # 3 GOOD $146,000.00 $243,000.00 # 4 FAIR $ 104,000.00 $165,000.00 Keep in mind that due to the high cost of restoration, mint examples of these cars can and have sold for more than the prices quoted here. Condition of a car CANNOT be determined by its location. Don't be fooled by a car's current geographical location. Just because a car is in California today, does not mean that is where it started life. The 300 four-door sedan convertible is a huge car and therefore VERY costly to restore. The large amounts of leather, wood and chrome add to the restoration costs. The late model cars are more refined and have more horsepower; therefore, they are more desireable.Rust tends to develop around the headlights and in the bar sections under the door sills. The trunk floors are prone to rust because of trapped moisture. Mechanical parts are readily available; however, trim items such as chrome are difficult to find. Look at the car in general. Walk around the car several times looking at the gaps for the doors, trunk and hood. Look at the general overall condition of the car. Where to find the engine number and chassis number: The chassis prefix for the 300 - 300a - 300b - 300c is 186 the engine prefix is also 186. The d series chassis prefix is 189 the engine prefix is also 189. Technical Specifications of the 300 Engine Type: 6 cyl overhead camshaft Bore and stroke: 85 x 88 mm Displacement: 2996 cc Power output: 115 hp (DIN) @ 4600 Compression ratio: 6.4:1 Torque: 20 mkg @ 2500 rpm Carburetion: 2 downdraft carburetors Solex 40 PBJC Engine speed at 100km/hr: 3300 rpm Gear ratios: I. 2.95:1 II. 2.13:1 III. 1.46:1 IV. 1.00:1 Rear axle ratio: 4.44 Chassis: X-shaped oval tubular Suspension: independent front, swing axle rear, with coil springs Brakes and area: drum, 1270 sq. cm Wheelbase: 3050mm Track front/rear: 1480/1525mm Length: 4950mm Width: 1838mm Height: 1600mm Ground clearance: 185mm Tires: 7.1 x 15 extra Turning circle: 12.6-13.1 meters Steering type and ratio: worm, 17.9:1 (4 turns) Weight: 4026 lbs Maximum speed: 99.5 mph Acceleration: 18 sec 0-100 km Fuel consumption: 16.5 L/100 km (14.2 mpg) Fuel tank capacity: 72 L (19 gal) Technical Specifications of the 300b Engine Type: 6 cyl overhead camshaft Bore and stroke: 85 x 88 mm Displacement: 2996 cc Power output: 125 hp (DIN) @ 4500 Compression ratio: 7.4-7.5:1 Torque: 22.5 mkg @ 2600 rpm Carburetion: 2 downdraft carburetors Solex 32 PAJAT Engine speed at 100km/hr: 3300 rpm Gear ratios: I. 3.44:1 II. 2.30:1 III. 1.53:1 IV. 1.00:1 Rear axle ratio: 4.67 Chassis: X-shaped oval tubular Suspension: independent front, swing axle rear, with coil springs Brakes and area: drum, 1470 sq. cm Wheelbase: 3050mm Track front/rear: 1480/1525mm Length: 5065mm Width: 1838mm Height: 1640mm Ground clearance: 185mm Tires: 7.1 x 15 extra Turning circle: 12.6-13.1 meters Steering type and ratio: recirculating ball, 21.4:1 (3.75 turns) Weight: 4026 lbs Maximum speed: 101 mph Acceleration: 17 sec 0-100 km Fuel consumption: 16 L, super (14.7 mpg) Fuel tank capacity: 72 L (19 gal) Technical Specifications of the 300c Engine Type: 6 cyl overhead camshaft Bore and stroke: 85 x 88 mm Displacement: 2996 cc Power output: 125 hp (DIN) @ 4500 Compression ratio: 7.4-7.5:1 Torque: 22.5 mkg @ 2600 rpm Carburetion: 2 downdraft carburetors Engine speed at 100km/hr: 3300 rpm Gear ratios: I. 3.44:1 II. 2.30:1 III. 1.53:1 IV. 1.00:1 Rear axle ratio: 4.67 Chassis: X-shaped oval tubular Suspension: independent front, single swing axle rear, with coil springs Brakes and area: drum, 1470 sq. cm Wheelbase: 3050mm Track front/rear: 1480/1525mm Length: 5065mm Width: 1838mm Height: 1600mm Ground clearance: 185mm Tires: 7.6 x 15 extra Turning circle: 12.6-13.1 meters Steering type and ratio: recirculating ball, 21.4:1 (3.75 turns) Weight: 4202 lbs. Maximum speed: 99.5 mph; 96.3 mph Acceleration: 17 sec 0-100 km; 18 sec 0-100 km Fuel consumption: 16 L, super (14.7 mpg) Fuel tank capacity: 72 L (19 gal) Technical Specifications of the 300d Engine Type: 6 cyl overhead camshaft Bore and stroke: 85 x 88 mm Displacement: 2996 cc Power output: 160 hp (DIN) @ 5300 rpm Compression ratio: 8.55:1 Torque: 24.2 mkg @ 4200 rpm Carburetion: Bosch injection pump Engine speed at 100km/hr: 3300 rpm Gear ratios: I. 2.303:1 II.1.435:1 III. 1.00:1 Rear axle ratio: 4.67 Chassis: X-shaped oval tubular Suspension: independent front, single swing axle rear, with coil springs Brakes and area: drum, 1470 sq. cm Wheelbase: 3150mm Track front/rear: 1480/1525mm Length: 5190mm Width: 1860mm Height: 1620mm Ground clearance: 185mm Tires: 7.6 x 15 extra Turning circle: 12.8-13.3 meters; from Sept. 1958, optional servo assist Steering type and ratio: recirculating ball, 21.4:1 (3.75 turns) Weight: 4400 lbs. Maximum speed: 106.5 mph; 102.5 mph Acceleration: 17 sec 0-100 km; 18 sec 0-100 km Fuel consumption: 17 L, super; 18 L. super Fuel tank capacity: 72 L (19 gal) A beautiful example of the luxurious Mercedes 300 convertible sedan.