🏷️ Basic Information

Make:

Mercedes-Benz

Model:

W114 / W115

Year:

1974

Chassis Code:

W114 (Luxury Sedan/Coupe), W115 (Standard Sedan/Diesel)

Model Series:

Mid-size luxury automobile

👋 Introduction

Vehicle Segment:

Mid-size executive sedans and coupes, positioned as premium vehicles in their era.

Key Competitors:

BMW 5 Series, Audi 100, Volvo 140 Series, Jaguar XJ6, American large sedans (though positioned differently).

Manual Advantage:

Provides exact, vehicle-specific information used by dealership technicians, ensuring accuracy and completeness unlike generic repair guides.

Digital Convenience:

All-in-one, searchable PDF manual eliminating the need for multiple physical books. Allows selective printing and digital storage.

📋 Manual Details

Primary Coverage:

All models and all repairs A-Z for 1974 Mercedes-Benz W114 and W115

Specific Topics:

Maintenance, Engine, Control System, Mechanical, Fuel Service, Emission Control, Intake/Exhaust, Cooling, Lube, Ignition, Starting, Charging, Automatic Transmission, Clutch, Manual Transmission, Transfer Case, Propeller Shaft, Drive Shaft, Differential, Axle, Suspension, Tires, Wheels, Brake Control, Parking Brake, Steering Column, Power Steering, Air Conditioning, Supplemental Restraint System (if applicable), Seat Belts, Engine Immobilizer (if applicable), Cruise Control, Wiper/Washer, Door Locks, Meter, Audio/Visual, Horn, Windshield/Glass/Mirrors, Instrument Panel, Seats, Engine Hood/Doors, Exterior/Interior Trim, Electrical Systems, Multiplex/CAN Communication (limited applicability for this era)

Estimated Page Count:

Extensive (exact number not specified, but implied to be comprehensive for A-Z repairs)

Type:

Factory Service and Repair Manual

Language:

English

Digital Format:

PDF

📖 Manual Coverage

Powertrain:

Engine (gasoline and diesel variants), Fuel System, Cooling System, Lubrication System, Ignition System, Starting System, Charging System, Exhaust System, Automatic Transmission, Manual Transmission, Clutch, Driveshafts, Differential, Axles.

Chassis And Suspension:

Front and Rear Suspension, Steering System (including power steering), Wheels, Tires, Brakes (front and rear, including parking brake).

Electrical And Body:

Wiring Schematics, Lighting, Instruments, Gauges, Wipers, Horn, Power Windows (if equipped), Door Locks, Air Conditioning, Heating, Exterior and Interior Trim, Body Panels.

Maintenance:

Scheduled maintenance, fluid changes, lubrication, filter replacements, tune-ups, inspections.

Diagnostics And Troubleshooting:

System-specific diagnostic procedures, fault finding, symptom-based troubleshooting, diagnostic charts.

Repair And Rebuild:

Step-by-step instructions for component removal, disassembly, repair, assembly, and reinstallation for major vehicle systems.

Detail Level:

Factory-level detail, intended for professional technicians. Includes torque specifications, clearances, timing settings, component identification, and diagnostic procedures.

📊 Manual Specifications

Digital Container:

PDF (Portable Document Format)

Printable Resolution:

High-resolution, allowing for clear printing of diagrams and text. Images can be enlarged for detailed viewing.

Digital Format Benefit:

N/A (Digital format, not physically bound)

Digital Format Benefit:

N/A (Digital format, printable on user's choice of paper)

⚙️ Engine Specifications

Engine Options 1974:

W114: M115 (2.3L I4), M110 (2.8L I6). W115: OM615 (2.2L Diesel I4), OM616 (2.4L Diesel I4).

Horsepower Range:

Approximately 90 HP (Diesel) to 140 HP (2.8L I6 Gasoline).

Torque Range:

Varies by engine, typically 120 lb-ft to 175 lb-ft.

Gasoline Induction:

Carbureted (e.g., Solex, Zenith) for most models. Fuel injection (Bosch K-Jetronic) may be present on some higher-end gasoline variants.

Diesel Injection:

Direct injection with Bosch inline fuel injection pumps.

🔧 Transmission

Manual Transmission Type:

4-speed or 5-speed manual (column or floor shift).

Automatic Transmission Type:

3-speed automatic (historically known as 'Hydrak' for earlier models, likely upgraded to conventional torque converter automatics by '74).

Transmission Control:

Mechanical linkages for manual, hydraulic for automatic.

📐 Dimensions

Wheelbase:

W114: 108.3 inches (2750 mm). W115: 108.3 inches (2750 mm).

Length:

W114 Sedan: 187.4 inches (4760 mm). W115 Sedan: 187.4 inches (4760 mm).

Curb Weight:

Approx. 3,000 - 3,400 lbs (1360 - 1540 kg), depending on engine and equipment.

🛡️ Safety Features

Crash Test Era:

Modern safety standards for the mid-1970s. Lacks advanced features like airbags or ABS found in later vehicles.

Braking System:

Front disc brakes, rear drum brakes. Power assist standard. Typically dual-circuit hydraulic system.

Steering System:

Recirculating ball steering, optional power steering.

Seatbelts:

Standard front seat belts, with provision for rear seat belts.

Body Construction:

Unitized body construction with crumple zones and safety cage designed for the era.

💡 Technology Features

Audio System:

Period-appropriate AM/FM radio, optional cassette player. Typically 1-2 speakers.

Cruise Control:

Optional, vacuum-operated or early electronic systems available on some models.

Vehicle Systems:

Basic electrical systems, no advanced digital networking like CAN bus. Focus on mechanical and analog electrical controls.

🔧 Maintenance

Oil Change Interval:

Typically every 3,000-5,000 miles (4,800-8,000 km) or annually, depending on driving conditions. Check manual for exact recommendation.

Tune Up Interval:

Spark plugs, ignition points (if applicable), and ignition timing checks generally recommended every 10,000-15,000 miles (16,000-24,000 km).

Engine Oil Grade:

API SF or SG classification. Viscosity typically SAE 10W-40 or 15W-40 depending on climate. Consult manual for precise OEM specifications.

Coolant Type:

Ethylene glycol based antifreeze/coolant. Mixture ratio typically 50/50 with distilled water.

Automatic Transmission Fluid:

Dexron-III or equivalent (check for specific MB specification for the era, e.g., MB 236.1).

Common Wear Items:

Brake system components (pads, rotors, lines), suspension bushings, exhaust system, fuel system components (fuel pump, injectors/carburetor), ignition components, engine seals (oil leaks).

Diesel Specifics:

Glow plug system reliability, injection pump maintenance, and potential for injector issues over time.

📚 Vehicle History

Mercedes Benz Legacy:

Mercedes-Benz is renowned for engineering excellence, durability, and safety, with a long history of innovation in automotive technology.

W114 W115 Development:

Introduced in 1968, the W114/W115 represented Mercedes-Benz's entry into a more accessible, yet still premium, mid-size segment. They replaced the W110 'Fintail' models and set new standards for comfort, ride quality, and build quality in their class.

Production Years:

1968-1976

Manufacturing Locations:

Primarily Germany (Sindelfingen), with some assembly in other global locations.

🏆 Awards & Recognition

Industry Acclaim:

Consistently praised for build quality, engineering, and longevity. Often cited as a benchmark for its class in terms of durability and refinement. Not typically subject to modern award structures but highly regarded by owners and critics of the era.