🏷️ Basic Information Identification Make: Mercedes-Benz Model: W123 E-Class Year: 1979 Codes Chassis Code: W123 👋 Introduction Market Position Segment: Executive mid-size sedan/coupe/estate, known for its robust engineering, luxury appointments, and durability. Competitive Analysis Competitors: BMW 5 Series (E12/E28), Audi 100, Volvo 240/260, Jaguar XJ, Cadillac Seville. Key Features Vehicle Reputation: Renowned for build quality, longevity, safety (for its era), and Mercedes-Benz's signature engineering. Manual Value Proposition: Provides critical, vehicle-specific technical data essential for accurate diagnosis, repair, and maintenance, enabling DIY enthusiasts and professional mechanics to service the W123 to factory standards. 📋 Manual Details Coverage Areas Engine Types Covered: All gasoline and diesel engines offered for the W123 E-Class in 1979, including M110 (2.8L I6), M115 (2.3L I4), OM615 (2.2L I4 Diesel), OM616 (2.4L I4 Diesel), and OM617 (3.0L I5 Diesel). Body Styles Covered: All body styles including Sedan (W123.043, W123.023, W123.103), Coupe (W123.053), and Estate/Wagon (S123.013). Page Count Estimated Page Count: Approximately 1000+ pages (typical for comprehensive Mercedes-Benz service manuals of this era). Manual Type Type: Factory Service Manual / Repair Manual Language Language: English Format Format: Print Replica / Digital PDF (depending on product offering) 📖 Manual Coverage Systems Covered Engine Mechanical: Detailed disassembly, inspection, assembly, and testing procedures for all engine components, including cylinder head, block, pistons, crankshaft, camshaft, timing systems, oil pump, cooling system, and lubrication. Fuel System: Comprehensive coverage of gasoline fuel injection (Bosch K-Jetronic) and diesel fuel injection systems (Bosch inline and rotary pumps), including component testing, calibration, and troubleshooting. Ignition System: Diagnosis and repair of ignition systems, including distributor, coils, spark plugs, and electronic ignition components. Transmission Manual: Service and repair procedures for manual transmissions, including clutch assembly, gear selection mechanisms, and internal component overhaul. Transmission Automatic: Detailed repair and adjustment of automatic transmissions (e.g., 4-speed 722.1 series), including torque converter, valve body, planetary gear sets, and hydraulic control systems. Drivetrain And Axles: Service for rear axle assemblies, differential, driveshafts, CV joints, and wheel bearings. Brakes: Repair and servicing of front and rear disc brakes (including caliper overhaul, pad replacement, rotor machining/replacement), parking brake system, and brake fluid specifications. (Note: ABS was not standard on W123). Suspension: Front and rear suspension component service, including shock absorbers, springs, control arms, ball joints, tie rod ends, sway bars, and bushings. Wheel alignment specifications. Steering: Power steering system diagnosis and repair, including steering gear, pump, hoses, and fluid specifications. Electrical System: Comprehensive wiring diagrams for all vehicle systems, starter motor, alternator, battery service, lighting, instrumentation, ignition switch, and accessory circuits. Climate Control: Service for heating and ventilation systems. A/C system (if equipped) diagnosis and refrigerant handling (R12). Body And Interior: Body panel repair, door and window mechanisms, upholstery, trim removal, and glass replacement. Procedures Included Maintenance Scheduling: Detailed recommended maintenance intervals for oil changes, filter replacements, fluid checks, tune-ups, and component inspections based on mileage and time. Troubleshooting Diagnostics: Systematic diagnostic procedures and flowcharts for identifying and resolving common and uncommon problems across all vehicle systems. Component Rebuilds: Complete instructions for the overhaul and rebuilding of major mechanical components like engines, transmissions, and differentials. Torque Specifications: Precise torque values for all critical fasteners and bolts throughout the vehicle. Special Tools: Identification and usage instructions for specialized tools required for specific repair and diagnostic procedures. Technical Depth Depth: Comprehensive, covering routine maintenance to full mechanical and electrical system overhauls. Equivalent to dealership-level technical information. 📊 Manual Specifications File Format Digital Format Features: Searchable text, hyperlinked sections (if digital), printable pages, high-resolution diagrams and schematics. Print Quality Print Quality Assessment: Professionally reproduced or original print quality, ensuring clear legible text and sharp, detailed diagrams. Binding Type Binding: Professional binding (e.g., saddle-stitched, perfect bound, or spiral bound for digital print-on-demand) for durability in a workshop environment. Paper Type Paper Quality: Durable paper stock, often heavier gauge than standard printing paper, suitable for repeated handling in garages and workshops. ⚙️ Engine Specifications Primary Engine Engine Options 1979: M110 (2.8L SOHC I6, 137-140 hp), M115 (2.3L SOHC I4, 93-104 hp), OM615 (2.2L OHV I4 Diesel, 55 hp), OM616 (2.4L OHV I4 Diesel, 62-72 hp), OM617 (3.0L OHV I5 Diesel, 72-80 hp). Performance Typical Top Speed: Varies by engine, e.g., 110-125 mph for gasoline models. Fuel System Gasoline Injection Type: Bosch K-Jetronic (CIS) continuous injection system. Diesel Injection Type: Bosch inline or rotary injection pumps. Engine Oil Recommended Oil Viscosity: Varies by climate and engine, typically 10W-40 or 20W-50. Refer to manual for specific recommendations and API service classifications (e.g., API SF or later for gasoline, CD or later for diesel). Engine Coolant Coolant Type: Ethylene glycol-based antifreeze with corrosion inhibitors. Capacity approximately 7-9 liters. 🔧 Transmission Standard Standard Transmission: 4-speed manual transmission (common on base models). Optional Optional Transmission: 4-speed automatic transmission (e.g., 722.1 series) was widely available. Features Automatic Transmission Features: Hydraulic torque converter, planetary gear sets, vacuum modulator...