March 1998 saw the world premiere of the Mercedes-Benz CLK convertible at the Geneva Motor Show, the first official photos and information having been available since December 1997. In June 1998, one year after the launch of the CLK coupé, the soft-top variant made its appearance in the showrooms at Mercedes-Benz sales outlets and authorized dealers in Europe and, since the fall of 1998, the new convertible has also been available on the USA and Japanese markets.
The soft-top CLK variant is effectively the successor to the 124 series E-Class convertibles, which had gone out of production one year earlier, and has been designed as an uncompromising four-seater. The new convertible is based technically and stylistically on the CLK coupé and also comes under the 208 series designation.
In non-convertible cars, the roof assembly plays an essential part in the rigidity and strength of the bodywork. When the roof is taken away, its absence has to be compensated by new structures, making a number of demands on the construction of the car. In the CLK convertible, engineers have therefore modified certain parts of the body-in-white by using thick or high-strength sheet metal and other materials to improve rigidity. These measures included reinforcing the center tunnel, side members, A-pillar assembly and B-pillar stump. In addition, extra connecting members were installed as an extension of the side members, cross members were built in under the driver and front passenger seats and a rear panel was welded to the bodywork. Diagonal struts at front and rear link parts of the body having critical amplitudes of movement in order to improve vibration and torsion resistance and enhance overall rigidity.
The newly developed semi-automatic soft-top consists of a solid steel and aluminum frame and a weatherproof fabric top made up of three layers with a specially smooth outer surface. Despite its complex construction, the soft-top is very simple to operate and still allows for generous trunk space. A central rotary handle on the windscreen frame is all that is needed to release or lock the soft-top and the rest of the work is performed by an electro-hydraulic servodrive activated by a pull/push switch next to the gear lever. This switch opens and closes the roof semi-automatically using the electro-hydraulic drive.
After working to good effect with the Wilhelm Karmann company in Osnabrück during the development of the SLK and CLK coupé, Daimler-Benz returned to the firm to seek its participation as a development partner for the CLK convertible. Given its years of experience in building convertibles, Daimler-Benz had no hesitation in transferring responsibility for final assembly to Karmann for the first time. The Daimler-Benz plant in Bremen supplied the basic bodywork parts and shared components for the CLK convertible, whilst the engines, transmission and axles are manufactured in Untertürkheim.
Like its coupé brother, the CLK convertible is available in two design and equipment lines - "Sport" and "Elegance" - which also differ in some external features: the "Elegance" model line has discreet chrome trim on the door handles and side window frames, as well as 5-hole light-alloy wheels. The "Sport" line emphasizes the dynamic character of the new CLK convertible by deliberately dispensing with the "embellishments" but featuring 7-hole forged light-alloy wheels.
Both lines have the same extensive range of standard equipment featured in the CLK coupé. This includes the ASR acceleration skid control system, outside temperature indicator, leather-covered steering wheel, remote trunk release, and tinted glass. The "Easy Entry System" provides convenient entry and exit for the rear seat passengers by pulling the front seats further forward. The rear seat backrests are split 1/3 : 2/3 and can be folded forward to further increase the capacity of the already ample trunk space.
The CLK convertibles, like the coupé model, is equipped with a large number of technical innovations, which all contribute to an increase in safety, comfort and economy. Particularly worthy of note are the ELCODE system, which optimizes anti-theft protection and comfort and is operated using an electronic door and ignition key, and "Brake Assist" (BAS), which can recognize when emergency braking is called for and, if necessary, automatically generate the maximum braking power in a split-second. Both systems, ELCODE and BAS, are elements of a high-performance data network which allows fast and reliable communication between the control units in the engine and the car interior. Daimler-Benz was the world's first automobile manufacturer to use a data interface to connect the individual local networks creating a comprehensive digital network.
Another innovation featured in the CLK coupés is, of course, also fitted in the new convertibles: The "Active Service System", known as ASSYST, improves efficiency by constantly monitoring the oil quality in the engine. This system allows need-related servicing intervals to be determined according to the actual operating conditions, increasing the gap between services from the previous 15,000 km to an average of 18,500 - 20,000 km.
As far as passive safety is concerned, the CLK convertible meets the 1998 crash tests standards for the European Union, as well as future US regulations. When developing the new convertible, Mercedes engineers paid particular attention to modern requirements, such as the protection of other road users and compatibility. In the event of a collision with another car, the front end of the CLK convertible is designed to dissipate the impact energy acting on the other vehicle. This feature particularly benefits the occupants of smaller cars. In addition to airbags for the driver and front passenger, the standard-fitted safety features of the CLK convertible include belt tensioners and belt force limiters for the front seats and side airbags in the doors, thereby providing an optimum level of occupant safety.
Special precautionary measures have to be in place in case the car overturns. If such an event occurs, the necessary survival space is maintained by the reinforced A-pillars, in combination with the robust windscreen frame and the roll-over bar. The roll-over bar, which has already proved effective in the E-Class convertible, is raised at lightning speed as soon as its sensors detect that the car is overturning. With this comprehensive safety concept, the soft-top CLK has set new standards in the convertibles market.
In Germany, the CLK convertible was initially available with a choice of three engines, identical to those used in the coupé model: the CLK 200 with a 2.0-liter, 4-cylinder unit and rated output of 100 kW/136 hp, the CLK 230 Kompressor with a supercharged 142 kW/193 hp 2.3-liter, 4-cylinder engine and lastly the CLK 320 with a V6-unit generating 160 kW/224 hp. In Italy, Portugal and Greece, countries with fiscal limits on engine size, the CLK 200 Kompressor was introduced in place of the 2.3-liter variant.
In August 1999, the new model year 2000 started for the successful Mercedes-Benz CLK coupés and convertibles with an even more extensive standard equipment and new, innovative technology systems. Up to this point, over 135,000 drivers worldwide had opted for the CLK, around 110,000 for the coupé and around 25,000 for the convertible. By that, the coupé more than doubled the sales figures of its predecessor from the 124 series. The CLK convertible reached the quantity the former four-seater convertible had achieved in its whole five year long production time in just two years.
The so called conquest rate of the attractive model series was also astonishingly high. It was at 40 % for the coupé, and with the convertible, Mercedes-Benz could even poach around 60 % of customers from other car manufacturers.