Market Position:
The Mercedes-Benz W123 series, particularly the 280E, represented the pinnacle of executive sedan engineering in its era, known for its build quality, durability, and comfort. This manual serves enthusiasts and owners seeking to maintain or restore these classic vehicles.
Competitive Analysis:
Competed with other luxury sedans of the late 1970s and early 1980s, such as BMW 5 Series, Audi 100, and Volvo 240, offering a more refined and robust driving experience, albeit at a higher price point.
Key Features:
Reputation for exceptional longevity and build quality, sophisticated engineering for its time, comfortable ride, and a robust yet smooth inline-six engine.
Target Audience:
Mercedes-Benz W123 280E owners, classic car restorers, independent mechanics, and automotive enthusiasts.
Coverage Areas:
Comprehensive service, repair, maintenance, troubleshooting, and diagnostics for the Mercedes-Benz W123 280E.
Page Count:
Estimated 1000+ pages (typical for comprehensive workshop manuals of this era).
Manual Type:
Service and Repair Shop Manual (Downloadable Digital Format)
Format:
Digital Download (PDF optimized for PC, Mac, Tablets, Smartphones)
Usability:
Cross-platform compatibility allows access on various devices, ensuring ease of use in the workshop or garage.
Update Status:
New & Updated for modern digital devices.
Systems Covered:
Engine Mechanical, Fuel System (Bosch K-Jetronic), Ignition System, Cooling System, Lubrication System, Exhaust System, Transmission (Manual & Automatic), Drivetrain, Suspension (Front & Rear), Steering System, Braking System (ABS Optional), Electrical System (Wiring Diagrams Included), Climate Control, Bodywork & Chassis, Interior Components, HVAC.
Procedures Included:
Routine maintenance, scheduled servicing, component removal and installation, engine overhaul, transmission overhaul, clutch replacement, brake caliper overhaul, suspension strut replacement, power steering system repair, electrical system troubleshooting, fuel injection system adjustment, emissions control system diagnosis, body repair, interior trim removal, body rust repair techniques.
Technical Depth:
Professional quality, in-depth coverage suitable for home mechanics and professional technicians. Includes detailed diagrams, step-by-step instructions, torque specifications, and diagnostic procedures.
Troubleshooting:
Includes systematic troubleshooting guides for common drivability, electrical, and mechanical issues.
Diagnostics:
Detailed diagnostic charts for engine performance, fuel system, ignition system, and electrical faults.
Electrical Schematics:
Complete, detailed wiring diagrams for all vehicle systems, essential for troubleshooting electrical faults.
Special Tools:
Lists and describes necessary special tools for specific repair procedures.
Body And Chassis:
Repair and maintenance procedures for body panels, frame, and structural components, including rust prevention and repair techniques.
Primary Engine:
M110.984 (2.8L, 2746cc) SOHC Inline-6
Horsepower:
177 hp @ 5800 rpm (DIN)
Torque:
234 Nm (173 lb-ft) @ 4500 rpm (DIN)
Fuel System:
Bosch D-Jetronic or K-Jetronic mechanical fuel injection
Cylinder Head:
Aluminum Alloy
Block Material:
Cast Iron
Bore X Stroke:
86.0 mm x 80.0 mm
Compression Ratio:
8.0:1 or 8.7:1 depending on market and emission standards.
Cooling System:
Water-cooled, thermostatically controlled, belt-driven fan.
Lubrication System:
Pressurized wet sump system with oil filter.
Injection Timing:
Specific timing procedures for K-Jetronic system, including cold start enrichment and warm-up regulator settings.
Emission Controls:
Details on emission control systems relevant to the W123 280E, including air injection or EGR where applicable.
Ignition System Type:
Distributor-based, Breaker Points (early) or Electronic Ignition (later).
Standard Transmission:
4-speed Manual Transmission
Optional Transmission:
4-speed Automatic Transmission (Model 722.1 or 722.3 depending on year)
Features:
Hydraulic clutch actuation (manual), torque converter lock-up (later automatics), robust construction.
Rebuild Procedures:
Comprehensive instructions for dismantling, inspecting, repairing, and reassembling both manual and automatic transmissions.
Length:
Approximately 4725 mm (186.0 in)
Width:
Approximately 1790 mm (70.5 in)
Height:
Approximately 1425 mm (56.1 in)
Wheelbase:
Approximately 2795 mm (110.0 in)
Curb Weight:
Approximately 1450 kg (3197 lbs)
Gross Vehicle Weight:
Approximately 1970 kg (4343 lbs)
Safety Ratings:
Not officially rated by modern standards (e.g., NHTSA, Euro NCAP), but designed with significant structural integrity for its time.
Active Features:
Four-wheel disc brakes (ventilated front), optional ABS (Anti-lock Braking System) on later models.
Passive Features:
Reinforced passenger cell, collapsible steering column, laminated front windshield, dual-circuit braking system.
Wheel Bolt Pattern:
5 x 112 mm
Tire Sizes:
Commonly 195/70R14 or 185HR14, refer to manual for specific fitments.
Infotainment:
Basic analog radio and cassette player options. Limited by the era's technology.
Driver Assistance:
Optional ABS on later models. Otherwise, driver-centric with focus on mechanical feel.
Connectivity:
N/A (No modern connectivity features).
Climate Control:
Manual or optional 'Thermatic' automatic climate control system, often vacuum-operated.
Service Intervals:
Oil changes: 7,500-10,000 miles (12,000-16,000 km) or annually. Major service: 30,000 miles (50,000 km) or as specified in the manual, including spark plugs, fuel filter, air filter, coolant, and brake fluid.
Engine Oil Spec:
API SG or SH, SAE 10W-40 or 10W-50 (consult manual for exact grade based on climate). Capacity: Approx. 7.5 liters.
Coolant Spec:
Ethylene glycol-based antifreeze mixed with distilled water (50/50 ratio). Capacity: Approx. 10 liters.
Transmission Fluid Auto:
MB-Approval 236.1 (e.g., Dexron III compatible). Capacity: Approx. 1.5-2.0 liters for change, 8.0 liters for overhaul.
Transmission Fluid Manual:
GL-4 rated gear oil, SAE 75W-90. Capacity: Approx. 1.5-2.0 liters.
Brake Fluid Spec:
DOT 3 or DOT 4.
Power Steering Fluid Spec:
MB-Approval 236.3 or ATF Dexron II/III. Capacity: Approx. 1.0-1.5 liters.
Known Issues:
K-Jetronic fuel injection system can be sensitive to vacuum leaks and component wear. Rust is a common concern, especially around wheel arches, rocker panels, and the battery tray. Overheating can occur if the cooling system is not meticulously maintained. Ignition system components (points, condenser, coil) require regular inspection and replacement. Vacuum hose degradation leading to various driveability issues.
Common Parts Replacement:
Fuel filter, air filter, spark plugs, ignition wires, distributor cap and rotor, fuel pump relays, vacuum hoses, thermostat, water pump, brake pads and rotors, wheel bearings.
Chassis Lubrication:
Procedures and specifications for greasing suspension and steering components (if applicable, pre-modern sealed units).
Engine Timing Belt:
N/A (M110 engine uses a timing chain).
Timing Chain Maintenance:
Details on chain tensioner inspection and replacement.
Brand Heritage:
Mercedes-Benz has a long-standing reputation for engineering excellence, luxury, and durability, established in the early 20th century.
Model Evolution:
The W123 replaced the W114/W115 series and was produced from 1975 to 1986, encompassing sedans, coupes, estates (S123), and long-wheelbase versions. The 280E was the top-tier gasoline engine option for many markets.
Production Years:
1976-1985 for the 280E variant within the W123 range.
Production Locations:
Primary production in Stuttgart, Germany, with assembly plants in other countries as well.
