Mercedes-Benz 220 b, 220 Sb, 220 SEb, 230 S, 230 SE, 300 SE, 300 SEL, W 111/112 (1959 to 1968)
In August 1959, the company announced a thoroughly revised passenger car range. Under the slogan: “The new six-cylinders – in a class of their own” and as successors to the existing six-cylinder models came the following three completely re-designed models – the 220 b, 220 Sb and 220 SEb of the W 111 series. In addition to various differences in equipment detail, the three new models also differed in terms of their engines. A coupé version of the 220 SEb arrived in February 1961, and a convertible followed in September that same year.
What the three saloons had in common, however, was an exceptionally spacious and elegantly styled body, the most distinctive features of which were its tailfins – a concession to the American influence on contemporary tastes. This characteristic design element would later give rise to the name by which the entire model generation came to be known – today the generic term “fintail” is applied to all these models.
The new model series set new standards in terms of passive safety, for these were the first production cars to feature the Barényi-patented rigid passenger cell with front and rear crumple zones. Safety was also given top priority in the design of the interior. The new models had a padded instrument panel, for example, with yielding and in part recessed controls, as well as a steering wheel with padded boss. Also worthy of note was the first use in this form of safety door locks, likewise major contributors to safety in the case of accident.
From the purely external point of view, the 220 b differed in eight features from its two sister models. The 220 Sb and 220 SEb, which were identical on the outside with the exception of the model designation, each had an additional chrome strip to either side of the radiator grille, a chrome-plated air intake grille in front of the windshield, and chrome-plated wheel trim. At the rear the differences were rather more apparent.
The two models with the “S” in their model designation had a chrome strip above the rear screen, an ornamental moulding to round off the trunk lid, larger rear lights with integrated license plate lamps, as well as additional bumper horns between the rear lamps and rear bumper. In addition, the tailfins – officially known as “guide bars” – had ornamental mouldings not only to the rear end-piece but also to the upper edge.
The engines were to all intents and purposes the same as those of the predecessor models but with minor modifications. All three units had modified valve control linkage and a steeper camshaft. The 220 b engine was now fitted with two carburettors and delivered 95 hp (70 kW), 110 hp (81 kW) in the 220 Sb. The direct injection unit for the 220 SEb featured straight intake pipes and developed 120 hp (88 kW).
The running gear and brake system also largely came from the predecessor models, although the suspension had been thoroughly revised in certain respects. At the front, the subframe design introduced with the ponton-type models was retained, although the shape was modified to a simple cross-member design joined flexibly to the frame floor at only two points. At the rear, the tried-and-tested single-joint swing axle was fitted with a compensating spring, positioned horizontally above the pivot point in order to distribute axle load equally to both drive wheels. The shock absorbers on the front and rear wheels were now positioned right on the outside, a measure that not only provided more effective vibration damping but also improved accessibility.
During the production period the brake system underwent two modifications. First the 220 Sb and 220 SEb were equipped with disk brakes to the front wheels in April 1962. Then in August 1963 the same modification was added to the 220 b and the model was simultaneously equipped with a brake booster – a feature available up until that point only at extra cost. As part of these changes, all three models were also fitted with a dual-circuit brake system, which offered safe retardation of the vehicle even when one of the circuits failed.
“Hydrak” hydraulic-automatic clutch
As with their predecessor models, the three new W 111 models were also optionally available with the “Hydrak” hydraulic-automatic clutch, although only until early 1962. After years of in-house development to reach production standard, a fully fledged automatic transmission was ready for use from April 1961, initially in the 220 SEb only, and then also from August 1962 upon order with the 220 b and 220 Sb – at an extra cost of DM 1,400. Unlike with the Borg-Warner automatic transmission available with the 300 c from 1956 and the 300 d successor model from 1957, the company’s own design did not use a torque converter, but instead relied on a hydraulic clutch. This had the advantage of reducing power loss. The downstream four-speed planetary gear train consisted of two planetary gear sets, three multi-plate clutches and three band brakes.