This comprehensive Mercedes 300D 1981 Service Repair Manual provides detailed instructions and guidance for a wide range of maintenance and repair procedures. It is designed to assist mechanics, enthusiasts, and owners in diagnosing vehicle problems and performing necessary repairs. The manual covers a thorough inspection process, encompassing components, lines, hoses, suspension, body structures, water leakage, and corrosion. It outlines procedures for essential maintenance tasks such as engine oil and filter changes, valve clearance adjustments, idle speed checks, injection timing checks, fuel filter replacement, air filter replacement, and V-belt inspections. The manual delves into the complexities of the vehicle's drivetrain, offering guidance on manual and automatic transmission fluid changes, transfer case fluid changes, clutch system inspections, throttle linkage lubrication, and level control system maintenance. It also includes instructions for maintaining the axles, wheels, tires, and brakes, encompassing procedures like brake fluid replacement, brake pad and disk inspections, parking brake adjustments, and power steering system checks. The manual extends its coverage to various vehicle systems, providing instructions for inspecting and maintaining the fuel system, exhaust system, battery, warning and indicator lamps, water drains, door hinges, door locks, hydraulic top, sunroof, soft top, windshield washer system, cassette deck, antenna, headlamps, wipers, and air conditioning system. It includes sections on cleaning and replacing various filters, lubricating components, and inspecting safety features. Finally, the manual offers guidance on removing and installing panels, checking for paint damage, and performing other essential maintenance tasks.

The 1981 Mercedes-Benz 300D, a stalwart of the W123 generation, represented a significant milestone in automotive history. This model, the successor to the iconic 240D, marked the arrival of a new, more powerful diesel engine in the Mercedes lineup. The 3.0-liter OM617 inline-five diesel engine, renowned for its durability and fuel efficiency, propelled the 300D to new heights of performance. Its naturally aspirated configuration delivered a respectable 88 horsepower and 133 lb-ft of torque, allowing the sedan to accelerate to 60 mph in a respectable 12.8 seconds. The 300D's four-speed automatic transmission provided smooth gear changes, ensuring a comfortable driving experience. Its robust build quality and timeless design, characterized by its boxy shape, simple yet elegant interior, and a focus on practicality, made it a popular choice for both private and commercial use. Beyond its performance and design, the 1981 300D cemented its reputation for reliability and longevity. With its robust diesel engine, sturdy construction, and a well-engineered drivetrain, the 300D earned a reputation for lasting countless miles with minimal maintenance. This unwavering reliability made it a favorite among taxi drivers, fleet operators, and owners who valued dependability and fuel economy. The 300D's simple yet effective design, combined with its remarkable durability, ensured its place as a classic, easily surviving the test of time. Today, the 1981 Mercedes-Benz 300D continues to be appreciated by enthusiasts and collectors for its historical significance, timeless elegance, and enduring reliability.