The merger between DMG and Benz & Cie. was completed on June 28/29, 1926. To mark the occasion, publicity material highlighted the combined power of the new brand that had been forged out of the two historic firms: “Germany’s two oldest and largest automotive companies have merged with a view to pooling over 40 years of experience in automotive design, the purchase of raw materials and production equipment and an extensive field organization, and to offering customers all over the world an unbeatable range of passenger cars and commercial vehicles.”
Benz & Cie. brought to the marriage two production locations: the stockholding company Benz & Cie., Rheinische Automobil- und Motorenfabrik, Mannheim, and Benzwerke Gaggenau. DMG transferred operational management of its plants at Untertürkheim, Marienfelde and Sindelfingen to the new company.
One of the new company’s first tasks following the merger was to conduct a clean-up of the two model portfolios. This had an impact on manufacturing at the Mannheim plant, where production of the 10/30 hp and 16/50 hp passenger cars from the old program initially continued under the new brand name Mercedes-Benz, before the new Mercedes-Benz Mannheim and Mercedes-Benz Nürburg models superseded these vehicles from the Benz era. The design office for passenger cars and the corresponding test facility were moved from Mannheim to the new company headquarters in Untertürkheim.
Tractors built at Mannheim also received the new name: in May 1928 the first few units of the new Mercedes-Benz OE diesel tractor rolled off the production line at the Mannheim plant. Offered as a vehicle for road and agricultural use, the tractor featured a water-cooled, horizontally mounted one-cylinder diesel engine that worked on the pre-combustion principle. Output of the large, 4.2-liter, single-cylinder unit was 26 hp (19 kW), achieved at just 800/min.
One of the customers of the Mannheim plant at this time was McLaren of Leeds. The tractor manufacturer (not to be confused with the racing stable of the same name, whose roots lie in New Zealand), signed a joint venture with Benz as early as 1926, advertising its tractor engines as “McLaren-Benz lightweight high-speed diesel oil engines.”
Was the plant ever threatened by closure?
Despite starting production of new models, the Mannheim plant entered a difficult phase during the worldwide economic crisis around 1930. Rumors about a possible closure began circulating as early as 1929. Frankfurter Zeitung wrote: “On the subject of a planned closure of the Mannheim operation reported from external sources, our own reporter at the site has heard that any such eventuality is out of the question following discussions between the company and the city of Mannheim. Operations there were running satisfactorily. The question of whether or not closure at Mannheim or relocation of production to Stuttgart may become an acute issue at some time in the future was dependent on developments in the automotive industry and wage developments at the two production facilities.”
The rumors fueled an immediate increase in the value of Daimler-Benz shares on the Berlin stock market, because investors envisaged a drop in production costs. In Mannheim, on the other hand, concerns turned to the question of whether or not closure of the plant was imminent. Motor-Post wrote in February 1930 that the number of workers at the Mannheim plant had risen from 2,800 (1928) to 2,900 (1929). But by May 1930, Neue Badische Landeszeitung reported that there had been 250 job redundancies. In fact the number of employees was cut from a high of 3,009 in 1929 to just 1,786 in 1930 – a drop of over one third. At the height of the global economic crisis in 1931, there were just 603 people at the Mannheim plant, and the lowest point was reached in 1932, with 374 employees – little more than one tenth of the 1929 workforce.
During this period of global economic crisis, the number of passenger cars built at Mannheim fell with equal rapidity. From 1,955 cars in 1929, production dropped back to 1,221 (1930), 515 (1931) and then 315 (1932). Nevertheless, the plant managed to escape full closure. On October 1, 1932, Berliner Börsenzeitung reported: “No closure of Daimler-Benz facilities in Mannheim for the time being.” Although consideration had been given to relocating production to Untertürkheim, the Ministry of the Interior for Baden intervened successfully. For the duration of the crisis the foundry was closed, however, and did not reopen until 1933.
The automotive industry as a whole received massive political support with the rise to power of the National Socialists early in 1933. Among other things, this led to a very speedy recovery of the employment situation at the Mannheim plant. That same year the plant was back to full employment and producing the two Mercedes-Benz Mannheim and Nürburg models. A new addition to the program was a 1.5-ton delivery van. And engines for commercial vehicles, boats, locomotives and tractors continued to play an important role in plant production. Finally, in 1937, the Mannheim plant also began truck production.
Second World War
An audit in 1939 underlined the important role the plant played in terms of Mercedes-Benz production as a whole: “In view of its outstanding technical facilities, the Mannheim plant has been assigned a particularly important responsibility within the production process of Daimler-Benz AG. In continuance of the old Benz tradition, Mannheim will be responsible for the production of diesel engines for industrial use, as well as for mid-range passenger cars and trucks. However, one of the Mannheim plant’s most important operational areas is to supply cast iron to all plants of Daimler-Benz AG from its exemplary and efficient cast iron foundry, a facility that operates with state-of-the-art equipment.”
The outbreak of the Second World War changed the situation of the Mannheim plant completely. The army forced operations to be switched to authorized production of the Opel three-ton truck. Demand for such vehicles during the war years was extremely high. As a result, the number of employees grew from 3,231 (1939) to 4,601 (1944). The workforce included 448 prisoners-of-war and forced laborers from the concentration camps, as well as 1,249 civilian foreign workers. The number of forced laborers and foreign workers reached a high in 1944. These people came from the Netherlands, Belgium, Italy, Poland, Russia, Czechoslovakia, Denmark, Croatia, Greece, Lithuania, Luxembourg, Serbia, Spain and Hungary.
For the Mannheim plant, the Second World War ended on March 23, 1945, when it was occupied by American troops. By this point, air raids had destroyed about 20 percent of all production facilities, and bombs had fallen on almost a quarter of the area. Following the occupation of the plant, a large area at the southern end of the premises was confiscated for use by the American occupying forces.