This comprehensive 1991 Mercedes S-Class W140 C140 Service and Repair Manual provides detailed instructions, diagrams, and specifications for maintaining, servicing, diagnosing, and repairing your vehicle. It covers all models and all repairs, offering the same information used by technicians at dealerships. You'll find step-by-step instructions, illustrations, wiring schematics, and specifications for every aspect of your vehicle.

This manual is designed to provide a complete and easy-to-use resource for all your car repair needs. It includes everything from routine maintenance to complex repairs, allowing you to tackle repairs with confidence. The manual covers a wide range of topics, including:

* **Maintenance:** Learn about routine maintenance tasks, such as oil changes, filter replacements, and fluid checks.
* **Engine:** Diagnose and repair engine issues, including problems with the fuel system, ignition system, and emissions control.
* **Control System:** Understand the complex electronic systems that control your vehicle, from engine management to safety features.
* **Mechanical:** Repair mechanical components, such as the transmission, suspension, brakes, and steering system.
* **Fuel Service Specifications:** Access detailed specifications for fuel system components, ensuring optimal performance.
* **Emission Control:** Learn about the emissions control system, its components, and how to perform repairs.
* **Intake Exhaust Cooling:** Diagnose and repair issues related to the intake, exhaust, and cooling systems.
* **Lube:** Find information on lubrication requirements and recommended fluids for various components.
* **Ignition Starting Charging:** Troubleshoot and repair issues with the ignition system, starting system, and charging system.
* **Auto Transmission Clutch:** Diagnose and repair problems with the automatic transmission and clutch system.
* **Manual Transmission:** Understand the workings of the manual transmission and learn how to repair common issues.
* **Transfer Propeller Shaft:** Learn about the transfer case, propeller shaft, and how to address potential problems.
* **Drive Shaft:** Diagnose and repair issues with the drive shaft, including potential damage or wear.
* **Differential:** Understand the functionality of the differential and how to perform repairs.
* **Axle Suspension:** Repair and maintain the axles and suspension system, ensuring a smooth and safe ride.
* **Tire & Wheel:** Find information on tire sizes, wheel specifications, and maintenance recommendations.
* **Brake Control:** Understand the braking system and its components, and how to diagnose and repair problems.
* **Brake:** Repair brake components, including the calipers, rotors, pads, and lines.
* **Parking Brake:** Diagnose and repair issues with the parking brake system.
* **Steering Column:** Repair the steering column and its components, ensuring safe and responsive steering.
* **Power Steering:** Troubleshoot and repair problems with the power steering system.
* **Air Condition:** Learn about the air conditioning system, its components, and how to perform repairs.
* **Suppl Restraint System:** Understand the supplemental restraint system (airbags) and its components.
* **Seat Belt:** Repair and maintain the seat belts, ensuring proper operation and safety.
* **Engine Immobilizer:** Diagnose and repair issues with the engine immobilizer system.
* **Cruise Control:** Troubleshoot and repair problems with the cruise control system.
* **Wiper & Washer:** Learn about the windshield wiper and washer system, and how to repair common issues.
* **Door Lock:** Repair and maintain the door lock system, including the locks, latches, and actuators.
* **Meter Audio/Visual:** Understand the instrument cluster, how to diagnose issues, and how to repair components.
* **Horn:** Diagnose and repair issues with the horn system.
* **Windshield/Glass Mirror:** Learn about the windshield, glass, and mirrors, and how to repair damage.
* **Instrument Panel:** Repair the instrument panel and its components, ensuring proper functionality.
* **Seat:** Repair and adjust the seats, including the upholstery, mechanisms, and electrical components.
* **Engine Hood/ Door:** Fix issues with the engine hood and doors, including latches, hinges, and seals.
* **Exterior & Interior:** Learn about the exterior and interior components, including trim, detailing, and repairs.
* **Electrical:** Understand the electrical system, how to diagnose issues, and how to repair electrical components.
* **Multiplex/ Can Communication:** Learn about the vehicle's multiplex communication system and how to diagnose and repair issues.

With this detailed manual, you'll have all the information you need to keep your 1991 Mercedes S-Class W140 C140 running smoothly and reliably.

The 1991 Mercedes-Benz S-Class W140 C140, affectionately nicknamed the "S-Class," represented a monumental leap forward for the German automaker. This luxurious sedan redefined the standards of opulence and technological advancement in the automotive industry. Its introduction marked an era of significant innovation, with features that were previously unheard of in a production car. The W140's design was a departure from its predecessor, the W126, showcasing a more imposing and stately presence. Its squared-off styling, punctuated by a prominent grille and expansive chrome trim, exuded an air of authority and prestige. The S-Class's oversized dimensions provided ample interior space, offering unrivaled comfort and luxury. The cabin was a haven of finely crafted leather, wood accents, and advanced electronics. Innovations such as electronic climate control, dual-zone air conditioning, and an integrated navigation system were introduced in this generation, solidifying the S-Class's position as a technological pioneer.

Beneath its luxurious exterior, the S-Class boasted a robust lineup of powerful engines, including the iconic 5.0-liter V8 and the 6.0-liter V12, both of which were renowned for their smooth and refined performance. The S-Class was engineered with a focus on safety, incorporating advanced features such as anti-lock brakes, Electronic Stability Program (ESP), and multiple airbags. The W140's advanced engineering and robust construction made it a highly reliable and durable vehicle, capable of covering vast distances with ease and comfort. The 1991 Mercedes-Benz S-Class W140 C140 was not only a symbol of luxury and refinement, but also a testament to Mercedes-Benz's unwavering commitment to innovation and engineering excellence. It established a benchmark for the modern luxury sedan and set the stage for future generations of the iconic S-Class.