By the end of the Second World War, the benchmarks had changed in Germany and Western Europe. People were suffering greater hardship, their needs were existential, their standards more modest, the newly elected Federal government in West Germany was closer to the people and democratic.

The Federal President and the Federal Chancellor initially used cars merely as a mode of transport – the Pullman saloons and cabriolets from the Mercedes-Benz, Horch and Maybach SW 38 brands from pre-war times; the Governing Mayor of Berlin, Luise Schröder, used a Model 170 V as her official car.

At first everyone at Daimler-Benz had other things to worry about than thinking about a remake or new design of the ‘Super Mercedes’. The overall economic situation was gloomy, characterised by the rapid collapse of the ruined Reichsmark. An improvement was only to come about with the currency reform and the introduction of the German Mark, but this did not happen until 20 June 1948. Wilhelm Haspel called a meeting on 22 December 1947 with the aim of discussing plans for a sports and representative car; for a time he was not Chairman of the Board of Management at Daimler AG due to denazification, and it was not until 1 January 1948 that he took on this position again. The aim of the meeting was to decide on a range of vehicles also suitable for export – even in such dark economic times, Haspel recognised the necessity for Mercedes-Benz cars with the appropriate charisma in the luxury segment: ‘But what is missing is a vehicle that gold-plates the name Mercedes-Benz again.

Another year and a half would pass, however, before Haspel’s ideas took shape on a more modest basis – in the period directly following the war, Central Europe had moved towards vehicles with a much smaller displacement. Initially priority was given to the Model 170 S (W 136 III, later W 136 IV), which Daimler-Benz brought out in 1949. Before the war it had originally been earmarked as the successor to the Model 170 V (W 136), and for two years it now assumed the role of the later S-Class in the Federal Republic of Germany in terms of price and social status. The two-seater Cabriolet A even became the country’s most expensive car. In 1951, the Model 220 (W 187) was launched, and it, too, was one of the S-Class’s forerunners.

Against this background, the Model 300 (W 186 II) which was unveiled at the same time was seen as a superlative-class car back then – something that was reflected in its price and performance as well as its appearance.

But in the meantime the development department took several approaches when it came to creating a vehicle that gold-plated the name Mercedes-Benz again. In order to keep costs and new invest­ments to a minimum in view of the difficulties involved in the procurement of machinery, existing stock was used up. Where the chassis and the bodies were concerned this meant the Model 230 (W 153) with the all-steel body from Daimler-Benz which had come out shortly before the war, plus the corresponding chassis with an X-type pipe with a wheelbase of 3050 millimetres. When it came to the engines the production units for the 2.6 litre M 159 engine had survived the bombings to such an extent that they could be built up again. This resulted in no less than 9004 units of this engine being produced between 1941 and 1944. Although originally intended for passenger cars, they were all installed in the 1.5-tonne L 301 model, which had carved out a career for itself as a small fire-fighting vehicle, and as a bucket-seat car. This engine had a hemispherical combustion chamber with V-shaped overhead valves, which were operated by the low-mounted camshaft via tappets.

The first deliberations regarding the construction of a more representative vehicle were made on the basis of this M 159 and the model series W 153. To begin with it was given the model series designation W 182 and was intended to have a displacement of 2.6 litres. In order to take into account the increasing vehicle weight, in 1949/1950 the engine was given a series of higher displacements in rapid succession: firstly 2.8 litres and finally 3.0 litres, with various model variant designations to match.

Tried-and-tested technology as the basis for development
The engine derived from the M 159 was known as the M 182, and whilst it still had a crankshaft with four bearings and a displace­ment of 2.6 litres, it already boasted a modified cylinder head with larger valves. This was where engine developer Wolf Dieter Bensinger fell back on a design list that had been put together as a stop-gap measure, and this resulted in the characteristic oblique contact surface between the cylinder head and the cylinder block for the engine which was now called the M 186 I and for the variant derived from it. It was in order to take over as many production machines as possible from the manufacturing of the M 159 on the one hand, and also to create room for larger valves in the cylinder head on the other, that Bensinger hit upon the idea of the oblique section, which provided the larger area that was needed.

Along with the increase in displacement the crankshaft was converted over from four to seven main bearings. This engine with the internal designation M 186 I still had overhead valves operated via tappets, but that changed with the advent of the M 186 II, which operated the valves via an overhead camshaft. It was not until a good year before the vehicle presentation at the International Motor Show in Frankfurt am Main (IAA) in 1951 that chief engineer Fritz Nallinger told his colleague Karl C. Müller: ‘The results of work involving the M 186/II engine with an overhead camshaft have now reached such a stage that this design can be described as promising. Therefore I would ask you only to firmly plan in the machines which are used for the 186/II design and to set aside the machines which are additionally needed for 186/I.

Somewhat confusingly, the engine described at the testing stage as the M 186 II was later given the designation M 186 I or just M 186. Meanwhile the first design of the Model 300 always bore the model series designation W 186 II.

On 27 March 1950, in a report about the Geneva Motor Show, Nallinger also informed his Board of Management colleagues about the development status of what was classified internally as the ‘Group B car’, the Model 300: ‘The cylinder volume has been increased to 3 l, the control shaft moved upwards into the head. This has resulted in the following advantages: better governing of the engine speeds with regard to valve control, so that engine speeds resulting in favourable valve-time cross sections are achieved with the steeply rising cam shape. This means that with the 3 l engine with the normal carburettor engine and intake manifold configurations 115 hp is achieved.

For reasons of time Nallinger now suggested building the body using stampings from the Models 170 S (W 136 IV) and 230 (W 153) and other new stampings. A solution that the Head of Body Testing in Sindelfingen, Karl Wilfert, who always tended to go his own way, set out in a letter to Wilhelm Haspel himself. But Wilfert had not reckoned on the reaction of his Chairman of the Board of Management. Haspel always had a very determined opinion on vehicles – when it came to both style and technology. He was completely opposed to Wilfert’s proposal and sent him the following reply: ‘Where the matter of shape is concerned, I believe that – even if you have fallen in love with this change – you will not contradict me when I say that this resultant object has become disproportionate and therefore decidedly inelegant. In short, there is no sense in wanting to change and modernise to such an extent an object that was created from a different overall design; the result will be a bastard and one should not do such a thing.

Hermann Ahrens, who had actually been taken on again after the war by Haspel to work on body design for commercial vehicles, buses and coaches, was commissioned by him to design the body for the model series W 186 II. Ahrens achieved a good compromise between the taste of the predominantly conservatively oriented customers influenced by pre-war Mercedes-Benz design and the expectations of the customers in the initial post-war years, who demanded forms that flowed much more, headlamps integrated into the body and the absence of running boards on a luxury Mercedes-Benz.

In actual fact, the frame of the model series W 153 served as the basis, and its wheelbase – measuring 3050 millimetres – was also retained, but the frame was dimensioned in accordance with the much higher weight of the model series W 186 II. The wheel suspensions corresponded to the latest standard at Daimler-Benz: at the front there were wishbones and coil springs. At the rear a dual-joint swing axle was used, which was designed especially for high levels of ride and suspension comfort. In order to ensure handling safety and comfort with a full load, a torsion-bar suspension which was electrically engageable via the dashboard was installed.

A surprise came in the form of the newly designed three-litre M 186 engine with an overhead camshaft and 115 hp (85 kW) at 4600 rpm. With a maximum speed stopped in tests by specialist journals at 158 km/h (‘auto motor und sport’), 160 km/h (‘Automobil Revue’, Bern) and 164 km/h (‘Motor Rundschau’ and ‘The Autocar’) it is Germany’s fastest car up until the unveiling of the Model 300 S (W 188) in October 1951, the latter being nothing other than the sporty two-door variant of the Model 300.

Linking up with the tradition of the ‘Super Mercedes’
The new Mercedes-Benz 300 top model presented in 1951 was a representative vehicle by central European standards, but compared with vehicles available internationally it was not. But as a represen­ta­tive vehicle with the more modest claim characteristic of those years it did connect with the tradition of the ‘Super Mercedes’. It was unveiled as a four-door, six-windowed saloon and as a four-door cabriolet, which was described in the Daimler-Benz nomenclature as the Cabriolet D.

From December 1952 onwards, the range of optional equipment features was extended to include a sliding sunroof and from March 1953 a partition between the driver’s area and the passenger compartment. Federal President Theodor Heuss and Federal Chancellor Konrad Adenauer accepted and adopted it as their official vehicle – in common parlance the car was even referred to as the ‘Adenauer’ 300. Legend has it that during the presentation in 1951 Adenauer asked General Manager Wilhelm Haspel in his Rhineland dialect: ‘Haven’t you got anything bigger?’. All the same he had his official car taken to Moscow when he visited the city in 1955, was driven in it to the Kremlin for his meetings with Nikolai Bulganin and Nikita Khrushchev and confidently and convincingly represented the young Federal Republic of Germany during its period of development.

The Model 300 also became a status symbol amongst many VIPs in Germany and abroad, such as King Gustav Adolph of Sweden and actors Gary Cooper, Errol Flynn and Fernandel, whose real name was Fernand-Joseph Désiré Contadin. The most famous customer of all was Pope John XXIII, whose specially designed 300 d Landaulet was one of the best-known Model 300 vehicles. The American Presidents from Dwight D. Eisenhower to John F. Kennedy were also driven through cheering crowds in the open-top Mercedes-Benz 300.

Under the headline ‘Might in moderation’ the Bern-based ‘Automobil Revue’ noted: ‘The tradition-bound, if also more relaxed, lines and the MB 300’s more powerful radiator which only varies slightly from the previous version, make it easy to overestimate its dimensions, which are modest compared with those of American cars.’ The Swiss went on to comment: ‘Anyone who changes over to the ’ But also: ‘The 300 is following the tradition of most European companies, which very rarely oversize their engines.’

In 1952, Werner Oswald attested to the Model 300’s superlative international class in ‘auto motor und sport’, summing up thus: ‘The engine performs fantastically. It’s not just its power and output – its elasticity, its refinement and its smoothness are delightful too. It is every bit the equal of the American throttle engines where the latter properties are concerned. Finally we want express how pleased we are that the Mercedes 300 also marks the German car industry’s return to the world market with a top product. In Untertürkheim they can be rightly proud of the fact that in building the MB 300 they have succeeded right away in creating a truly top-grade specimen.

In its test no. 1467, the British journal ‘The Autocar’ wrote of the Mercedes-Benz Model 300: ‘There are very few saloon cars which are capable of a mean speed of over 100 mph, but to obtain this result on a five-six-seater saloon car with generous room for passengers and luggage, using an engine of three-litre capacity said to deliver only 114 bhp is a notable achievement. The suspension and handling qualities offer a combination of riding comfort, stability and safety which reaches the pinnacle of current achievement. The ride is soft enough for the most fastidious passenger, but is very damped, and there is no sensation of roll, even when travelling really fast over winding roads.

There is no noticeable tendency to understeer or oversteer; if forced to the limit, the rear end will begin to slide, but in a way which is instantly controllable by a flick of the wheel. The Type 300 of Mercedes-Benz is clearly a very strong competitor for the favour of the most discerning international buyers, to whom it will appeal because of its performance, detail finish and equipment. It maintains a high general level of excellence.

In 1951, the year it was launched, another 43 vehicles were built. The reason for the fact that the price for a vehicle without tyres was indicated was that in those days there were market prices for tyres and their price was stipulated on delivery.

The express mention of a heater might cause surprise, but back then this was not a standard feature of many vehicles – including those from other manufacturers – though it always was in the Model 300, for instance, even if it was expressly mentioned in the price list.

According to the price list dated December 1952, at that time there was also a sliding canvas sunroof available for 750 DM, and from March 1953 for 950 DM there was also a partition between the passenger compartment and the driver’s area.

The Mercedes-Benz 300 b (W 186 III)
In Untertürkheim they were very much aware of the high expecta­tions that were placed by the customers on a premium product like the Model 300, so work went on incessantly to perfect it. The fruits of these labours were presented at the Geneva Motor Show in 1954 in the form of the Mercedes-Benz 300 b (W 186 III).
The exterior identifying features of the Model 300 b were the bumper guards on the front and rear bumpers, which the previous Model 300 only had for its export version. The vent windows in the front doors symbolised major progress where ventilation was concerned. The chromed perforated wheel rims ensured better heat dissipation from the larger – now ribbed – brake drums, referred to back then as turbocooling. The driver was supported by a standard-specifica­tion vacuum brake aid – another new feature which had not been included in the previous Model 300.

The engine output was increased by 10 hp (7.4 kW) to 125 hp (92 kW) at 4500 rpm, which brought with it a consumption cut at the same time; ‘auto motor und sport’ records 17.3 litres over 100 kilometres for the Model 300, and for the Model 300 b 15.6 litres. Several measures were responsible for this. The increase in compression from 1 : 6.4 to 1 : 7.5 played a decisive role, as did the changeover from two Solex model 40 PBIC two-stage compound downdraught carburettors to two Solex model 32 PAJAT downdraught carburettors with two mixing chambers whose throttle valves open one after the other depending on the position of the accelerator. Further progress made by the new carburettor system also included the automatic choke, which provided a richer mixture for a cold start.

A lot of journalists from the motoring press also described the Model 300 b as being a ‘superlative’ vehicle (‘Motor-Rundschau’) or a ‘diplomat’s car’ (‘auto motor und sport’). The partition between the driver’s section and the passenger compartment which was available as an option for this model from 1955 onwards also befitted its status as a diplomat’s car.

The Mercedes-Benz 300 c (W 186 IV)
For the International Motor Show in Frankfurt in September 1955, the Model 300 was again brought closer in line with the model range of the times in technical terms, and became the Model 300 c (W 186 IV). From the exterior it could only be distinguished from the 300 b predecessor model by the larger rear window and the larger tyre size, 7.60 x 15. Along with the wider tyres there was also a changeover to wider wheel rims with size 5.5 K x 15 B, which were later also used for the Models 300 d (W 189) and 300 SL Roadster (W 198 II), but were not recognisable at first glance. The two most important changes concerned the chassis and the drive system. In the chassis a single-joint swing axle now also replaced the dual-joint swing axle for the largest passenger car model from Mercedes-Benz, ensuring better driving characteristics. The new feature in the drive system was the inclusion of the automatic Borg-Warner DG 150 M transmission with three gears as part of the standard specification. As the manual four-gear transmission was now only available optionally and with a deletion allowance, the Model 300 c was the first German passenger car that was only supplied with a manual transmission as an option. Above all it was chief engineer Fritz Nallinger and export boss Arnold Wychodil who drove forward the inclusion of the automatic transmission in the Model 300 with a view to the American market, and who did not wish to wait any longer for the completion of the company’ own automatic transmission, which would only come into use another six years later.

In June 1956, a sales information bulletin mentioned a long-wheel­base version of the Model 300 for the first time, though this was not reflected in the price lists. The body and wheelbase had been extended by 100 millimetres. By also moving the rear seats back 40 millimetres, the legroom had been boosted by 140 milli­metres. It was the German Federal Chancellor Konrad Adenauer who initiated this design. At the beginning of March 1956 chief engineer Nallinger told his Board of Management colleagues the following about the Model 300 c: ‘I have included the car with an extended wheelbase, as in the version we shall be delivering for Federal Chancellor Adenauer. I think that we could include this extended wheelbase from September. The car can then accordingly be offered for sale at a higher price than the usual sales price.

It was only a few months before the expiry of Model 300 c in July 1957 that a footnote in the price list valid from March 1957 mentions the extended-wheelbase version. There is no separate mention of this late addition to the product range in the model variant and production lists which were otherwise always meticulously updated. Production of the large cabriolets had already ceased in mid-1956.

The Cabriolet D was no longer listed as of price list no. 4 dated 3 May 1956, analogous to the end of production in June 1956.

The extended version (with a wheelbase of 3150 millimetres) of the Mercedes-Benz 300 c (W 186 IV) cost 3000 Deutschmarks according to price list no. 5 dated 1 March 1957.

The version with an extended wheelbase was not given a separate model variant designation.

The Mercedes-Benz Model 300 d (W 189)
The Model 300 received its most extensive revision in autumn 1957, resulting in a new model series designation, W 189. Not only did the longer wheelbase represent the standard dimensioning with immediate effect; the overall look of the vehicle had changed considerably: Hermann Ahrens turned his final passenger car design into reality. The tail end with the gently contoured side wings and the vertical tail light layout corresponded to those of the Model 220 coupé/cabriolet (W 180) and was given a larger boot. The front was also redesigned. The headlamps received trim rings projecting forwards in keeping with the style of the time. The rectangular fog lamps integrated into the wings formed a contrast to the round main headlamps.

Progress for the driver came in the form of the large rear window which extended over the entire width and was wrapped around the sides. In conjunction with the retractable side windows and thanks to a 30-per-cent increase in the overall window area this helped to create a totally new sense of light and space and a better all-round view. At the time this concept was referred to as the ‘pillarless full-vision body’.

With an eye to the American market the Model 300 d had very much been brought into line with the expectations regarding driving which existed there. Examples of this included the suspension tuning which differed considerably from that of the original Model 300 and was now designed for comfortable, relaxed cruising. This impression was underlined by the smoother but also more indirect manual steering and the power-assisted steering which was optionally available with the standard-specification automatic transmission. The three-gear automatic transmission enabled the car to stand still on a slope without rolling backwards. Plus, when gear ‘D’ was engaged the first gear could now also be activated at speeds below 40 km/h by fully depressing the accelerator (‘kickdown’). In the predecessor it had only been possible to shift down from third to second gear in this way.

Passengers’ wellbeing was enhanced by air conditioning from December 1958 onwards. Due to the additional charge that came with it, when the announcement about this new feature was made it was noted: ‘A cooling system has been developed for the 300. The gross price for this has been set at DM 3500. As this price hardly covers the material costs, a discount cannot be granted.

The engine output was increased from 125 hp (92 kW) to 160 hp (118 kW) through the introduction of indirect manifold injection, so as to compensate at least partially for the higher vehicle weight. The tank capacity of 72 litres, which had been regarded as very mediocre, was now raised to 79 litres.

Within the exclusive series of the Model 300 d there was a special feature in the form of three vehicles specially built in 1960 which differed significantly from the usual saloons: a landaulet delivered to the Vatican for Pope John XIII., a second landaulet from the company’s fleet which was loaned to the Federal government for state visits, and a saloon for the same purpose with a large sliding steel roof in the rear. These cars differed greatly from the normal vehicles of the model because of their wheelbase, which was extended from 3150 to 3600 millimetres. The overall length grew from 5190 to 5640 millimetres, the width from 1860 to 1995 milli­metres and the height from 1620 to 1720 millimetres. The car’s weight went up by 375 kilograms to 2365 kilograms.

Leather upholstery (680 DM) and power steering (only with an automatic transmission, 750 DM) were not included in the price list. The prices were quoted in circulars no. 25/57 dated 12 September 1957 and no. 40/58 of 3 March 1958.

According to circular no. 67/58 dated 1 December 1958 the air conditioning cost 3500 DM. And the Cabriolet D was not included in the price list either – with an automatic transmission it cost 37,000 DM and with a manual transmission 35,500 DM, according to circular no. 69/58 dated 15 December 1958.

In the mid-1950s, Daimler-Benz acknowledged that the Model 300’s era was coming to an end, so head engineer Fritz Nallinger initiated work on a new ‘Super Mercedes’ with the model series designation W 100. It was unveiled in 1963 as the Mercedes-Benz 600.

However, with the Model 300 the company had created a viable link between the Mercedes-Benz passenger cars, the Germany of the post-war period and young Federal Republic – both in terms of the vehicle’s proportions and the stylistic reorientation that occurred in the years following the war. A Model 300 d as a vehicle for the Pope in the Vatican’s fleet did not appear like an exotic foreign body – it looked as though it had always belonged there.

Source: Daimler AG