Mercedes-Benz W126


The [Mercedes-Benz S-Class|]Mercedes-Benz W126 is the company's internal designation for its second generation
S-Class, manufactured in sedan and coupe configurations, succeeding the company's W116 range.
Mercedes introduced the 2-door C126 coupé model, marketed as the "SEC", in September 1981, based on the standard wheelbase S-Class sedan.
Over the twelve years,1979-1991, W126 S-Class production reached 892,123 — including 818,063 sedans and 74,060 coupés. It is the most successful S-Class in term of the number of units produced and the duration it was in production.
The S-class nameplate is an abbreviation for the German Sonderklasse or "special class."

History

Following the debut of the 1970s generation W116, Mercedes-Benz began plans for the next-generation S-Class model in October 1973. Codenamed "project W126," the project aimed to provide an improved ride, better handling, and improved fuel efficiency, to help retain the model's marketing position. Mercedes-Benz made fuel efficiency a goal, in the large V8 engined versions of the S-Class.
The W126 design team, led by Mercedes-Benz's Bruno Sacco, sought to produce a car that was more aerodynamic than the previous model. The application of lighter materials and alloys combined with thorough wind tunnel testing to reduce overall drag meant the car consumed about 10% less fuel than its predecessor. The W126 featured the first seatbelt pretensioners.
After six years of development, the W126 was introduced at the Internationale Automobil-Ausstellung in Frankfurt on September 1979. The initial range featured seven models in standard and long wheelbase sedan body styles: the 280 S/SE/SEL, 380 SE/SEL, 500 SE/SEL and 300 SD. The long-wheelbase variants were internally codenamed V126. In 1981, the coupé version C126 of the W126 S-Class premiered at the IAA with the 500 SEC model. In 1981, Wheels Magazine selected the W126 model 380 SE as its Car of the Year.
Although the top of range Mercedes-Benz 450 SEL 6.9 of the previous generation was not directly replaced, the W126 carried forward the hydropneumatic suspension of the 6.9 as an option on the 500 SEL and later on 420 SEL and 560 SEL models.
Four years after the introduction of the fuel-efficiency "Energieskonzept" in 1981, the model range was extensively revised. In September 1985, again at the IAA in Frankfurt, the revised model range was introduced. Apart from visual changes to the bumpers, side covers and larger 15-inch wheels with a new design on the hubcaps and alloys, there where technical upgrades as well as revised engine availability. A new generation of inline-six petrol and diesel engines and new 4.2- and 5.5-litre V8s were added, and other engines were revised.
The W126 generation was replaced by the W140 in 1991, although a satellite factory in South Africa continued limited production until 1994.

Styling

From 1973 to 1975, Mercedes-Benz designers worked on the successor to the W116. In December 1975, after several design concepts being presented, the design for the W126 S-Class was approved and frozen in 1976. Design work on the coupe began immediately afterward, being finalized in 1977.
Compared to its predecessor, the W116, the W126 featured improved aerodynamics. The W126 was the first Mercedes equipped with polyurethane deformable bumpers. Design patents were first filed on March 3, 1977 and later on September 6, 1977 at the United States Patent Office.
In 1985, Mercedes-Benz issued a facelift for the W126, with revised bumpers, body side protection mouldings, and wheel designs. The 14" alloy rims largely standardized throughout the MB family since 1969 were replaced with the 15-slot flat-faced silver painted alloy rims.
The interior featured pleated leather on the doors and leather seats in the North American markets; while global markets offered velour seating trim. Zebrano wood trim was used on all S-Class models during the first phase of the generation's run with burled walnut available in the second phase the 560SEC and 560SEL.

Models

The W126 series initially included the 280, 300, 380, and 500 series models. Following the first S-Class mid-cycle refresh, the W126 series included 260, 300, 350, 420, 500, and 560 models. Variants included SE, SEL, SEC, and diesel models.

Features

Features included the following safety, comfort, and technological features.

Safety

First Series
At the introduction in September 1979, the 2.8-litre DOHC six-cylinder inline M110 engine for 280 S, 280 SE, and 280 SEL was carried over from W116. The new generation of M116/M117 V8 engines had a significant innovation: aluminium block without iron sleeves as found in the competitors’ engines. Mercedes-Benz developed a special silicon coating as to harden the cylinder liners against excessive wear and tear. The V8 engines were offered in two sizes: 3.8 litres and 5.0 litres. The smaller of two V8 engines was offered in the US market only, which turned out to be a disaster with timing chain issues and due to being severely underpowered. The S-Class coupés were fitted with V8 engines only for the first time.
The 3.0-litre five-cylinder inline OM617 diesel engine was carried over from W116 with same performance. Inexplicably, the diesel engines were again never offered in the markets outside United States and Canada. The lethargic acceleration, roughness, and lower top speed might not appeal to the European consumers who had higher expectations for the large saloons. This discrepancy wasn't addressed until 1994 when W140 S 350 TURBODIESEL was introduced in Europe for the first time.
In 1981, Mercedes-Benz introduced the “Energiekonzepts” programme in reducing the fuel consumption. This programme revised the combustion chambers and piston heads with lower compression ratio in the V8 engines. This revision caused further drop in engine performance.
Second Series
For the second series introduced in September 1985, the engine range was extensively revised with new six-cylinder inline engines and enlarged V8 engines. Only 5.0-litre M117 V8 was carried over from the first series, expanding the V8 engine range to three.
The revised engine range focused more on reducing pollution and fuel consumption even further. For the first time, the customers outside US and Canadian markets could choose the models with or without catalysators. The models without catalysators can be retrofitted with catalysators at later date if the customers choose to: this retrofit method is called RÜF. The RÜF models had a mechanical switch in the engine bay to be operated by owners for running on lead or lead-free fuels, a necessary feature for driving outside Germany or in areas within Germany where the lead-free fuel wasn't widespread yet. In 1990, all engines were fitted with catalysators only.
The new six-cylinder inline M103 engine had a single overhead camshaft and electronic-mechanical fuel injection and was available in two sizes: 2.6 and 3.0 litres. The carburetted engine fitted to 280 S was eliminated, marking the end of carburetted engines for S-Class, and replaced with fuel-injected engines for 260 and 300.
The V8 engines were again bored out to 4.2 litres from 3.8 litres for 420 and 5.5 litres from 5.0 litres for 560 while 5.0-litre V8 for 500 was carried over. The V8 engines were fitted with new electronic ignition system and Bosch KE-Jetronic electronic-mechanical fuel injection system, first appeared in W201 190E. The revised V8 engines except 5.0-litre version had slight performance increase.
The most powerful engine ever fitted to W126 S-Class was 5.5-litre V8, putting out 221 kW. This engine, classified as ECE-Variante, has higher compression ratio of 10:5 and cannot be retrofitted with catalysator at later date. In September 1986, the ECE-Variante was superseded by RÜF-Variante, which retains the same horsepower figure without catalysator and lower figure if retrofitted with catalysator at later date. The 560 SEL with 221 kW engine was fastest large saloon, reaching 250 km/h, until BMW 750i/750iL was introduced in 1987 with ungoverned top speed of 300 km/h. Its performance was comparable to Porsche 911 Carrera 3.2 or Ferrari Mondial. In 1990, 560 SEL had a reduced horsepower figure to
For the US and Canadian markets, a new 3.0-litre six-cylinder inline OM603 diesel engine was introduced, replacing five-cylinder engine with same displacement. It was a first six-cylinder passenger diesel engine by Mercedes-Benz. This new engine was available in long wheelbase version only, 300 SDL, for the first time. For California, the diesel engines were fitted with diesel particulate filter, a world's first for the passenger car. The new engine had an ill-gotten reputation for higher percentage of aluminium cylinder head failure due to poor placement of diesel particulate filter and due to the erosion of head gasket, allowing cooling fluid to seep in the cylinders. However, they failed to perform as designed and were removed from the engines. For 1988, the engine was revised to correct the issues and move the particulate filter further away from the engine. In 1990, the same engine was bored out to 3.5 litres as to compensate for reduced performance due to stricter emission regulations. The bored out 3.5-litre version did not have any of aforementioned issues other than some units experiencing the unexplained erosion of head gasket. The 3.5-litre version was available in both standard and long wheelbases.

Transmissions

First Series
The automatic transmission had four speeds with direct drive in the fourth gear for the entire run from 1979 to 1991. The 280S, 280SE, and 280SEL had 4-speed manual transmission as standard with 5-speed manual and 4-speed automatic transmissions as extra-cost options.
The manual transmission was not fitted to the V8 engines during the first series. The 300SD Turbodiesel had automatic transmission as sole transmission choice.
Second Series
From 1986 onward, the automatic transmission was revised to include the option of selecting S and E shifting points. The models, 260SE, 300SE, and 300SEL were fitted with standard 5-speed manual and optional extra-cost 4-speed automatic transmissions. For one year from September 1986 to June 1987, extra cost automatic transmission option wasn't offered for 260SE and 300SE. The customers ordering 420SE could choose either 5-speed manual or 4-speed automatic transmission.

Technical Data

First Series, 1979-1985

Second Series, 1986-1991

Dimensions and weight

Timeline

Special variants

  • AMG offered body kits for all W126 models, as well as a widebody kit for the coupé. AMG also offered many levels of engine tuning, but was most famous for the DOHC 6.0-litre engine, based on the original 117.968 engine. Also offered was a Gleason Torsen differential in varying ratios, manual transmission, and various TV/radio consoles.
  • Trasco Bremen offered a stretch limousine version called the "1000 SEL".
  • A variety of coachbuilders offered convertibles based on the SEC model. Caruna of Switzerland also offered a full four-door convertible based on the SEL. One of these still belongs to Dutch Royal Family, who use it at their resort in Porto Ercole, Italy.
  • Like the current model S-Guard, specially modified W126 S-Class models were produced for the transport of dignitaries and world leaders. Among the modifications made included a wheelbase stretch, bulletproof glass, and armored body panels.

    U.S. Grey Import Market

From its introduction in the United States in late 1980, Mercedes-Benz offered solely a smaller 3.8-litre version V8, to address fuel mileage concerns realated to the 1979 oil crisis and the subsequent 1975 US federal Corporate Average Fuel Economy requirements. The more fuel efficient V8, allowed Mercedes to avoid a CAFE penalty.
As the economy rebounded and expanded, demand increased for more powerful 500 SE/SEL/SEC models as the grey market imports. About 22,000 Mercedes-Benz vehicles, including 500 SE/SEL/SEC, were imported from Europe per year until 1987 when the loophole for personal import was closed and regulations for grey import tightened.

Racing

Two AMG-modified 500 SEC cars raced at the 1989 24 Hours of Spa. Both cars failed to finish, with one suffering gearbox issues, while the other had issues with the rear axle.

Awards

The W126 model 300 SD received the1981 Motor Trend Import Car of the Year. The W126 model 380 SE was the Wheels Magazine Car of the Year in 1981, the W126 was awarded the U.S. Highway Loss Data Institute "Safest Passenger Car of the Year" in 1988 and 1989, and the W126 was the third-ranked luxury vehicle in J.D. Power's 1990 Initial Quality Survey. From 1987-1990, Mercedes received the highest customer ratings in the J.D. Power Sales Satisfaction Index.

Legacy

The W126 series was the highest volume S-Class on record in terms of production. Three armoured 560 SEL ordered by Saddam Hussein had a series of pipes shooting the flames out of sides.
A limited number of W126 continued to be produced in South Africa until 1994, three years after the introduction of W140 S-Class. No figures were given for South African production. Nelson Mandela was given a commemorative model, a red 500 SE. His 500 SE was the last W126 assembled in South Africa and with components donated by Mercedes-Benz South Africa.

General

  • Workshop manuals

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