This manual covers the 300 D sedan and coupe, chassis code W114/W115, produced for the 1975 and 1976 model years. Renowned for its exceptional longevity, robust construction, and engineering excellence, the 300 D embodies a commitment to durability and comfort in the mid-size luxury segment. These vehicles, powered typically by the OM615 inline 4-cylinder diesel engine, were designed for individuals seeking reliable and comfortable transportation, competing with other luxury marques of the era. Their build quality and engineering philosophy have cemented their reputation for reliability, often exceeding half a million miles with appropriate care. This comprehensive Factory Workshop Service Repair Manual provides in-depth guidance for the maintenance, diagnostics, and repair of your 300 D. It covers all major systems, including the engine, transmission, brakes, suspension, steering, and electrical systems, detailing everything from routine oil changes and filter replacements to complete component overhauls and rebuilds. The manual is an indispensable resource for owners, mechanics, and technicians, offering factory-level insight and procedures to ensure the continued optimal performance and longevity of these classic vehicles. Its extensive coverage includes troubleshooting guides and technical specifications, presented in English for broad accessibility.