Description:
The Mercedes-Benz W123 series, particularly the 280E model, represented a pinnacle of build quality, durability, and engineering for its era. It was positioned as a premium mid-size luxury sedan and estate, known for its robust construction and comfortable ride.
Competitors:
Competed with other luxury and executive cars of the late 1970s and early 1980s, such as BMW 5 Series (E28), Audi 100, Volvo 240/740, and American large sedans from Cadillac and Lincoln.
Design:
Iconic 'Bauhaus' design language characterized by clean lines and a strong, upright stance. Excellent visibility and spacious interior.
Durability:
Renowned for exceptional build quality and longevity, often referred to as 'over-engineered' for their robustness and resistance to corrosion.
Comfort:
Supple ride quality, comfortable seating, and a well-insulated cabin contributed to a refined driving experience.
Savings:
This comprehensive service manual enables owners to perform their own maintenance and repairs, saving significant costs associated with dealership or independent mechanic labor.
Applicable Models:
Mercedes-Benz W123 280E
Applicable Years:
1976, 1977, 1978, 1979, 1980, 1981, 1982, 1983, 1984, 1985
Estimated Page Count:
Likely extensive, typical of factory service manuals for this era (e.g., 1000+ pages when considering all sections).
Type:
Workshop Service Manual (WSM)
Engine:
Comprehensive coverage of the M110 inline-six engine, including diagnosis, repair, overhaul, tuning, and component specifications.
Fuel System:
Detailed information on the Bosch K-Jetronic fuel injection system, including pump, injectors, air flow meter, control pressure regulator, and troubleshooting.
Ignition System:
Explanation of the electronic ignition system, including distributor, coil, spark plugs, and timing adjustments.
Transmission:
Service and repair procedures for both manual and automatic transmissions, including fluid changes, clutch service, and transmission overhaul.
Drivetrain:
Coverage of the rear-wheel-drive system, including driveshafts, universal joints, differential, and axles.
Suspension:
Detailed information on front and rear suspension components, including shock absorbers, springs, control arms, bushings, and alignment procedures.
Steering:
Repair and maintenance of the power steering system, including steering box, pump, hoses, and troubleshooting.
Brakes:
In-depth coverage of the hydraulic brake system, including master cylinder, brake lines, calipers, pads, rotors, and ABS (if equipped).
Electrical System:
Comprehensive electrical schematics, wiring diagrams, component testing, and troubleshooting for all onboard electrical systems.
HVAC:
Diagnosis and repair of the heating, ventilation, and air conditioning system, including refrigerant, compressor, and controls.
Bodywork:
Information on body panel removal and installation, door mechanisms, trim, and glass replacement.
Interior:
Details on interior components, upholstery, dashboard, and console removal/installation.
Routine Maintenance:
Oil changes, filter replacements, fluid checks and top-offs, spark plug replacement, belt inspections, battery maintenance.
Troubleshooting:
Systematic diagnostic procedures for common and uncommon issues, fault code interpretation (where applicable).
Repair:
Step-by-step instructions for component removal, repair, and reinstallation across all vehicle systems.
Overhaul:
Detailed procedures for engine, transmission, and differential overhauls, including component specifications and clearances.
Wiring Diagrams:
Complete and detailed wiring schematics for all electrical systems, color-coded for clarity.
Depth:
Professional quality, in-depth coverage suitable for DIY enthusiasts and professional mechanics alike. Covers everything from basic maintenance to complete engine and transmission rebuilds.
Type:
4-speed Manual Transmission (e.g., Getrag)
Type:
4-speed Automatic Transmission (e.g., ZF 4HP22 or Mercedes-Benz 4G-Tronic)
Manual Clutch:
Dry single-plate clutch
Manual Gearbox Oil:
API GL-4, SAE 75W-90 or 80W-90 (check specific manual for exact MB spec)
Automatic Transmission Fluid:
MB 236.2, ATF Dexron II (check specific manual for exact MB spec)
Crash Test Performance:
While formal crash test ratings as we know them today were less prevalent, the W123 was engineered with a robust passenger cell, crumple zones, and strong pillars, reflecting Mercedes-Benz's commitment to safety.
Brakes:
Four-wheel disc brakes (front ventilated) were standard on the 280E, offering strong stopping power. Optional ABS was introduced later in the W123's lifecycle.
Construction:
Reinforced chassis and body structure, safety-padded dashboard, collapsible steering column.
Seat Belts:
Three-point seat belts standard in the front, lap belts in the rear.
Audio System:
Typically featured Becker radio/cassette players, often with manual tuning and basic amplification.
Dashboard:
Functional and well-laid-out dashboard with analog gauges, including tachometer, speedometer, fuel level, oil pressure, and coolant temperature. Climate control vents and switchgear.
Cruise Control:
Optional on some models, a primitive form of cruise control was available.
Phone Integration:
Not applicable for the era; mobile phones were not integrated into vehicle systems.
Oil Change:
Typically every 10,000-15,000 km (6,000-9,000 miles) or annually, whichever comes first (check specific manual for exact intervals).
Air Filter Replacement:
Every 20,000-30,000 km (12,000-18,000 miles) or as needed based on driving conditions.
Spark Plug Replacement:
Typically every 20,000-40,000 km (12,000-24,000 miles), depending on plug type.
Coolant Flush:
Every 2-3 years or as per manual recommendations.
Engine Oil:
API SG/SF or equivalent, SAE 10W-40 or 10W-30 (check manual for specific MB approval like 228.1 or 229.1 for gasoline engines).
Coolant:
Ethylene glycol based, typically a 50/50 mix with distilled water. MB approval 325.0 (or equivalent).
Brake Fluid:
DOT 3 or DOT 4 (check specific manual)
Common Problems:
Rust/corrosion (especially on wheel arches, sills, and door bottoms), vacuum hose deterioration (affecting central locking, climate control, and engine idling), injector seal leaks, K-Jetronic system tuning issues, transmission accumulator plunger (for automatic transmissions).
Oil Filter:
Example: Mann-Filter W114/1, Mahle KL16 (verify exact part number for M110 engine with filter manufacturer).
Air Filter:
Example: Mann-Filter C2561, Mahle LX64 (verify exact part number for M110 engine with filter manufacturer).
Mercedes Benz Legacy:
Mercedes-Benz has a long-standing reputation for engineering excellence, safety, and luxury stretching back to the early 20th century. The W123 continued this tradition, built on the foundations laid by previous successful models.
W123 Lineage:
The W123 succeeded the W114/W115 ('Stroke Eight') series and was produced in various body styles, including sedan (Saloon), estate (T-model), coupé, and long-wheelbase limousine. The 280E was the flagship petrol model for much of its run.
Global Production:
Over 2.7 million units of the W123 series were produced worldwide across all body styles, making it one of Mercedes-Benz's most successful models.
Manufacturing Locations:
Primary manufacturing took place in Germany, with assembly plants also located in other countries.
