Curbside Classic: 1951-1962 Mercedes 300 (W186&189) – The Adenauer Mercedes; A Timeless Classic

Mercedes 300 W189 sfq

(Tan Mercedes 300d shots posted at the Cohort by nifticus)

(first posted 8/8/2015)   For decades, the number “300” associated with a Mercedes had almost mythological significance in Germany. And for good reason, as the long line of fine cars, sports cars and racers that carried that number on its backside were inevitable something special and expensive. The line started with the 300 sedan that arrived in 1951, trimmed and priced to compete with the Rolls Royce. It was built through 1962, when it was replaced by the Grosser 600. And it came to be closely associated with West Germany’s first post-war chancellor, Konrad Adenauer, who oversaw the explosive resurgence of the economy and rode in 300s. Like Adenauer himself, the 300 was a bit long on tooth, but that didn’t keep either of them from being loved, admired and being timeless classics in their day.

Mercedes Sindelfingen plant_1945

Not surprisingly, the Mercedes plants in Sindolfingen were a prime target during the war. The result was devastation…much of the facilities were destroyed by Allied bombers. Yet perhaps ironically, Mercedes was better positioned after the war than almost all of the other German car makers except VW, who had been either dependent on Ambi-Budd to build their bodies, which was destroyed and its ruins now located in East Berlin, or found themselves altogether on the wrong side of the Iron Curtain.

Mercedes 170-V

Mercedes managed to get their smallest car, the four-cylinder pre-war 170V, back in production in May 1946, albeit at very low volumes. It was a start, if not a very glamorous one, considering all the superb large and expensive cars Mercedes had been building before the war.

Mercedes 170S_5715

In 1949, it was augmented by the 170 S, featuring a more attractive body riding essentially the same chassis, and whose body’s origins were in the pre-war six-cylinder 230. For the time being, the 170S was the most luxurious Mercedes, despite having a modest little 52 hp 1.7 L flat head four. German dignitaries either rode in prewar Mercedes, or like the mayor of west Berlin, rode in a 170S. Incidentally, the 170 S might well be the true origins of what came to be known as the “S Class”, a special (“Sonder”) version of the basic Mercedes line.

By 1948, Mercedes could see a future again, and the first discussions of a new large car were initiated. By 1949, with the new DM having resolved the currency situation, the outlook was substantially improved, and the effort to create a new flagship was begun, one that would make it clear to the world that Germany was back.

Mercedes 300 1951_1

The new Mercedes 300 (W186) was unveiled in 1951, and the case was made rather convincingly. The 300 was designed to compete with the likes of Rolls Royce, whose very traditional Silver Dawn made the 300 look positively avant garde, despite its rather conservative design.


Mercedes-Benz Typ 300 (Baureihe W 186 II, 1951 bis 1954), X-Ovalrohrrahmen, Foto aus dem Jahr 1951. Der Typ 300 wurde in mehreren Baureihen insgesamt von 1951 bis 1962 gebaut.

Under the skin, the 300 was a mixture of old and new; more of the former, actually. The frame was a modified and strengthened version of a prewar tubular X-frame chassis as used in the 230 series, with coil sprung independent suspension on all wheels, the front by wishbones and the rears via the Mercedes-typical swing axles. An electrically-adjustable torsion bar was also used in the rear to automatically provide stable ride height (and wheel camber) regardless of the load.

Mercedes 300 M186 engine

Unlike the all-new M180 smaller six that also appeared in 1951 in the 220 line, the M186 “big six” was not really an all-new engine. The block was a development of the prewar M159 engine, a 2.6L ohv six designed for passenger car use but that ended up in a light war-time truck instead. The block, which was rather massive, was modified to have seven main bearings and increased displacement, and a new SOHC alloy cylinder head was designed. But the spark plugs were still in the pre-war position in the side of the block, not the head; a rather unusual design. The massive block was also a challenge in adapting this engine for the 300SL, and is one of the reasons Rudolf Ulenhaut used a very light tubular frame for the Gullwing coupe to help compensate for its prodigious weight.

Mercedes 300 M186 block

Those plugs in the block had me wondering about the combustion chamber and cylinder head. Engine developer Wolf Dieter used the angled top of the block with the integral combustion chamber to increase the valve size by overlapping the bore, to improve breathing and volumetric efficiency. Somewhat curiously, Mercedes was not a hemi-head adherent, and had been developing alternate methods for some time, which generally involved large intake valves mounted directly over the piston (or offset, as in this case) with a very direct intake port.

Mercedes 300 M186 cyl head

Here’s the cylinder head, which is flat like the Chevrolet “W” engine heads (348 & 409), and some others that had combustion chambers in the block. Mercedes achieved some stellar results with this head design; the direct fuel injected 300SL Gullwing engine version made 215 (net) hp from 183 cubic inch displacement; or about 250 hp gross. That’s a significantly higher specific output than the brand new 1957 fuel injected Corvette 283 CID (4.7 L) V8 that made 283 gross hp, this from a significantly smaller engine. The fact that the M186’s output was steadily increased from 115 hp to 215 hp was a testament to the soundness of this somewhat unorthodox cylinder head.

Mercedes did use a DOHC hemi-head design for their all-out racing engines, like the 300SLR’s and W196’s 3 Liter straight eight, but didn’t use hemis for its street cars until the 1973 M11o DOHC six, a development of the smaller M180 six that first appeared also in 1951.

Mercedes 300 design b

The evolution of the 300’s design presented some challenges. Initially, Mercedes-Benz Body Chief Engineer Karl Wilfert created a proposal that was essentially a pre-war 230 (W153) body, with a few updates like extending the front fenders into the front door. But CEO William Haspell was not happy with it, as these words of his make quite clear;“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.” I suspect his words were a bit more clear in their original German. Haspell then gave the job to Hermann Ahrens.

Mercedes 300 design a

This proposal presumably is one of the designs he came up with before the finalized version was agreed upon and put into production.

Mercedes 300 W186 side

It was clearly a modernized take on late 30s design elements,which given that the 300 was essentially just that, it’s not surprising. Mercedes had become conservative, in part out of necessity, and would not come out with reasonably modern new post war car until 1954, with the “pontoon” 220 (W180). But Ahrens did a fine job in balancing the classical and more modern themes, in a car that what was clearly best served at the time by not being too leading edge

Mercedes 300 1951 conv w186

As used in the first series 300 saloon and cabriolet, the M186 used twin Solex carbs and made 115 hp, enough to make it capable of a 100mph cruising speed. The British journal ‘The Autocar’ gave this glowing account of their test of the 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.

Mercedes 300 W186 rear

The 300 went on sale in the US in 1953, with the very lofty price of $6,500, or almost twice the price of a Series 62 Cadillac sedan.

Mercedes 300 S cabrio 1956

And that was well-topped by the 300S Cabrio and Coupe (W188), which featured a shorter wheelbase and hand-built bodies as well as prices some 50% higher as the 300 sedan. Engine power was upped to 150 hp.

Mercedes 300S coupe

These were bought by the elite celebrities and such of the time; they were the post war counterpart to the Duesenberg and other classics of the prewar era. The front view is by far the best one of these very valuable cars, but we need to give the tail a bit of equal time.

Mercedes 300 Adenauer1

Konrad Adenauer (here getting into the front of a 300 during his 1953 campaign), along with other heads of state (and the pope), made do with the 300 sedan or Cabriolet. But supposedly he did say “haven’t you got anything bigger?” when first shown the 300. Well, it wasn’t really all that big, especially in its width, despite the impression it may create from the imposing front end.

Mercedes 300 Adenauer-W-186-022

It was not well suited for three-abreast seating. The 300’s chassis was based on the pre-war 230, a car not approaching the true big pre-war Mercedes, like the 500/540K or the truly large 770 (Grosser) that Hitler had ridden in. Perhaps his comment spurred the development of the Grosser 600?

Mercedes 300 W189 rrq

Adenauer wasn’t quite around long enough for that really big new 600, which was announced in September 1963, one month before he left office. But his question got a partial answer in the substantially revised 300d (now W189) that arrived in 1957. It had a four inch wheelbase stretch, presumably to the betterment of rear seat foot room for Adenauer and the other dignitaries who might have been feeling a bit cramped back there.

Mercedes 300d w189 640x362

The 300d’s styling was revised and updated, and the sedan was turned into a stunning six-window hardtop, perhaps the only one of its kind. Never have the occupants of a closed car had such unobstructed views, or been on such display.

Mercedes 300 w189 girls

Inside or out.

Mercedes-Benz tpe 300D - 1958

There were numerous changes and upgrades to make the 300d more competitive, especially in the American market, which was so lucrative thanks to the willingness of well-heeled customers willing to pay lofty prices for cars like this. The 1958 300d listed for $10,418, still about twice what a Cadillac four door hardtop cost. The 300d now came standard with a 180 hp fuel injected version of the six, and had an automatic transmission and available power steering. Even air conditioning was available. And in case you’re wondering, a diesel engine was decidedly not available.

Mercedes 300 C stude-packard

The suspension was also softened and the manual steering was slower, all part of making the 300 more of a typical luxury cruiser and less of a serious road car. That’s not so say it still wasn’t exceptionally capable at speed, but comfort now took a higher priority. This was also during the time Studebaker-Packard was the exclusive distributor for Mercedes. That was convenient, since many Packard dealers became Mercedes dealers after the storied luxury car firm failed.

Mercedes 300 w189 int

The 300 was built the way the great classics were in the pre-war era, almost completely by hand. The interior was the of the finest possible craftsmanship.

Mercedes 300 w189 int dash


This 1961 300d has the newer padded safety-hub steering wheel, but the rest of the dash, exquisite as the materials and workmanship are, is starting to show its age. As was the rest of the 300, of course.

mercedes 300 1957 cabrioimages_1

It was a testament to the 300’s advanced prewar underpinnings that this car could still impress folks with many of its qualities right to the end, in 1962. It was a living classic, and folks knew it at the time, just like the last of the W111 280 SE 3.5 convertibles that were built until 1971.

Mercedes 300 w189 cabrio fq

Buyers knew they were getting the last of the line, but an exceptional car that would never really look “wrong”, despite the changing fashions of the time. This is a car that wears its genuine landau bars proudly, unlike the fakes that soon littered so many American brougham. This car was a classic, in its own time, and ever since.

Mercedes 600 -Grosser

The 300 was replaced by the 600, which was probably twice as good in every objective parameter. Impressive though it is, in its looks and capabilities, it will never quite equal the 300’s classic grace and timelessness.

mercedes 300d 1957_pictures_1

Never mind its hardtop roof.


Related reading:

Mercedes 300SEL  (W109): Trying To Make Sense Of The Magic Number “300”  by Don Andreina