Effortless superiority: W 123 series (1975 to 1985)
- Mercedes-Benz introduces the brand’s first station wagon in 1977
- The coupé is even produced in a diesel version
- Testing of alternative drive concepts
In January 1976 Mercedes-Benz introduced the 123 series saloon. It stepped out into the limelight for the first time with all the poise and assurance of being best in class. Classic body lines placed this new Mercedes-Benz in the tradition of its predecessor (W 115/114); they gave the new car modern elegance, a spirited but dignified look, and natural authority. This was no automotive revolutionary strutting out before the public, but a completely mature car of the upper mid-size category in which up-to-date technology and tried-and-tested engineering merged with the brand values. Much as expected, experts and customers alike gave the model a very warm welcome.
In various ways the design of the W 123 pointed towards the future: technically, with numerous innovations in the area of safety; and aesthetically, with a design that took its cue from the looks of the new S-Class W 116 and the current R/C 107 SL models. Expressions of this were the horizontally configured headlamps, for example, instead of the previous classic vertical lamps. The W 123 impressed with the high standard of its workmanship, its functionality, and its particularly wide range of body variants and engines. From 1977 this model series included the first production station wagon manufactured in-house by Mercedes-Benz.
Greater safety, improved comfort and better serviceability: these were the demands made of the Mercedes-Benz design engineers when the specifications for the new model series were drawn up in 1968. Almost eight years later it was apparent that the experts from Stuttgart had accomplished their task in a convincing manner. It was precisely the high level of safety engineering and the mature overall design that secured this model the attention of the trade press and the customers from the very beginning.
The formulation of the specifications book laid the foundation for developing the future intermediate class model. In the years that followed, new design sketches were repeatedly thrown into the ring, demonstrating just how large the spectrum of possibilities for the design of the new Mercedes-Benz was: attempts at gentle renewal of the existing model series stood at one end of the spectrum of the studies; at the other, futuristic visions with sharp edges, roofs with huge overhangs at the back, steep rear windows and massive rubber bulges around the body. But the boldest designs remained in cold storage. By 1973 the shape of the W 123 was known for the most part; work merely had to be done on the detail. Preliminary prototypes were under way by 1974. The vehicle safety test series began with impact tests in the summer of 1974. In 1975 comprehensive winter testing in Sweden was on the agenda.
In developing the new model the design engineers set particular store on an even higher level of safety for the occupants. This was a topic of increasing debate in the 1970s and resulted in new regulations. On January 1, 1976, the Federal Republic of Germany made the wearing of seat belts for front seat passengers compulsory. In keeping with this trend, vehicle development focused on restraint systems and passenger compartments designed to minimise sources of injury. The engineers also considered integrating airbags, but these were not installed until 1982 as an optional extra in the W 123.
1975: Brilliant premiere
Perfect preparation was the slogan prior to the start of series production. For the first time at Mercedes-Benz a so-called pilot line was set up to build the W 123. On this training line, equipped similar to the future production facilities, workers practiced assembling the W 123. In all, 16 cars were produced there in summer 1975.
The meticulous preparation paid off, for the new model got a resounding reception from the public. Soon after presentation of the W 123 the first year’s output was sold out; in 1976 young used cars of the series often fetched the price of a new car. Because of the long delivery times, among other reasons, Mercedes-Benz continued to build the “Stroke 8” for a whole year parallel to the new model. Taxi drivers, in particular, important customers in the intermediate range, had pressed for this offer.
Innovations and tried-and-tested technology
In technical terms the 123 series was an entirely new design, but was modelled both on its predecessor (W 115/114) and the new S-Class of 1972 (W 116). From the “Stroke 8” series the new model adopted in particular the engines, though with one exception: the newly designed 2.5-litre six-cylinder engine of the Mercedes-Benz 250 (M 123).
Other features borrowed from the S-Class included the double-wishbone front suspension, in which the steering swivel axes of the wheels were aligned so that their imaginary extension coincided with the contact patch of the tyre on the roadway. This neutral setting (zero scrub radius) ensured that the wheels would not be deflected inwards or outwards during braking. The double-wishbone front suspension meant the elimination of the subframe, which had been introduced in the “Ponton” and presented the engine, transmission and front suspension as a unified whole. At the rear of the W 123 was a diagonal swing axle, which had proven its value in the W 115/114.
Occupant safety was served particularly by the combination of an even sturdier passenger compartment with large crumple zones: the front and rear ends of the vehicles were designed for controlled deformation in a collision to absorb appreciably more impact energy than was the case in earlier designs. The central section of the body, the so-called safety cell (patented in 1951 as “shape-retaining occupant compartment surrounded by energy absorbing zones at the front and rear”), had even more stability owing to the incorporation of stronger box sections in the roof frame and the six roof pillars. Stronger door beams ensured better impact protection.
The steering column of the 123 series was also optimised with a view to the driver’s safety: a corrugated tube connected the jacket and the steering gear with each other. In an accident, the corrugated tube could buckle in different directions. This reduced the danger of the steering column penetrating into the passenger compartment (lance effect). This and the rigid passenger compartment with crumple zones were inventions of Béla Barényi, the pioneer of passive vehicle safety at Mercedes-Benz. Installation in the W 123 marked the premiere of the safety steering column, patented in 1963, as a complete system.
When Mercedes-Benz put the new intermediate class saloon on the market in 1976, its place in the current Stuttgart model generation was recognisable at a single glance. Like the S-Class W 116 and the new SL of the 107 series, the W 123 had horizontal headlamps instead of the upright configuration of earlier days. The great majority of models illuminated the roadway with round headlamps in pairs behind a common rectangular lens. In 1976 this was the first hint of the “four-eyed” face of the 1995 E-Class (W 210) and its successor of 2002 (W 211). Only the top-of-the-range versions 280 and 280 E had rectangular halogen wide-band headlamps at the premiere of the W 123. In the 1982 facelift these rectangular lamps were then introduced for all versions and all body variants.
The lines of the saloon, from which the other body variants derived, impressed in 1976 by integrating up-to-date elements while paying regard to the established concept: draft designs during the planning period had put forward many variations for consideration, but neither the large roof-level rear spoilers nor the fastback concepts got beyond the drawing board. At the premiere of the new model the W 123 was offered not only as a saloon, but as a chassis too, in keeping with Mercedes-Benz tradition. Mainly Binz (Lorch) and Miesen (Bonn) built ambulances on this basis; hearses were created by Pollmann (Bremen), Rappold (Wülfrath), Stolle (Hanover) and Welsch (Mayen). The chassis with standard wheelbase (2.80 metres) was given the series number F 123 and were initially offered as the 240 D and 230. The extended chassis with a wheelbase of 3.43 metres (VF 123) was initially available for the 240 D, 300 D and 250.