🏷️ Basic Information

Make:

Mercedes-Benz

Model:

W123 280E

Year:

1978

Generation:

First Generation W123

Chassis Code:

W123

Engine Code:

M110 (likely 2.8L inline-six)

👋 Introduction

Positioning:

Essential resource for owners and mechanics of the W123 280E, offering professional-grade repair information

Comparison To Alternatives:

More cost-effective than purchasing overpriced physical manuals or relying solely on online forums

Value Proposition:

Inexpensive way to keep the vehicle working properly, providing in-depth, factory-level detail

Usability:

Easy to navigate with a numbered table of contents, allowing quick access to information

📋 Manual Details

General Coverage:

Complete factory workshop service and repair

Specific Models Covered:

Mercedes-Benz W123 280E (all styles)

Estimated Page Count:

Hundreds of pages (exact count not specified, but implies comprehensive)

Type:

Workshop Service Repair Manual

Language:

English

File Format:

PDF

Delivery Method:

Digital Download

📖 Manual Coverage

Engine:

Complete engine overhaul, diagnosis, and repair

Fuel System:

Fuel injection system (likely Bosch K-Jetronic), fuel pump, fuel lines, and tank

Ignition System:

Distributor, ignition coils, spark plugs, and related components

Transmission:

Automatic transmission (likely 4-speed 722.1) overhaul, diagnosis, and repair

Drivetrain:

Rear axle, driveshaft, universal joints, differential

Suspension:

Front and rear suspension components, shock absorbers, springs, control arms, bushings

Steering:

Power steering system, steering box, tie rods, steering column

Brakes:

Front and rear disc brakes, hydraulic system, brake lines, master cylinder, calipers, pads, rotors

Electrical System:

Comprehensive electrical system diagnosis, troubleshooting, and repair, including wiring diagrams

Cooling System:

Radiator, water pump, thermostat, hoses, fan, coolant

Exhaust System:

Exhaust manifold, pipes, catalytic converter (if applicable for the region), muffler

Body And Chassis:

Body panel removal and installation, frame repair (if covered), glass replacement

Interior:

Dashboard, seating, trim panel removal and installation

HVAC:

Heating and ventilation system components and service

Maintenance:

Scheduled maintenance, fluid changes, filter replacements, lubrication

Troubleshooting:

Detailed diagnostic procedures for common and uncommon issues

Repair:

Step-by-step repair instructions for all major vehicle components

Disassembly And Assembly:

Complete disassembly and reassembly of major components and sub-assemblies

Electrical Diagnostics:

Wiring diagrams, component testing, circuit analysis

Engine Rebuild:

Complete engine overhaul procedures, including specifications and tolerances

Transmission Overhaul:

Detailed steps for rebuilding the automatic transmission

Depth:

Full factory level, suitable for professional mechanics and experienced DIY enthusiasts

Instruction Style:

Step-by-step numbered instructions, with substeps

Illustrations:

Hundreds of detailed illustrations, drawings, and photos

Critical Information:

Notes, cautions, and warnings highlighted throughout

Diagrams:

Detailed wiring diagrams integrated with electrical troubleshooting

Part Identification:

Enlarged inset views for detailed part examination

📊 Manual Specifications

File Type:

PDF

Compatibility:

All PC-based Windows operating systems and Mac

Software Requirement:

Adobe PDF Reader

Printability:

Printable without restriction (entire manual or selected pages)

Binding:

N/A (Digital Download)

Paper Quality:

N/A (Digital Download - user prints as needed)

⚙️ Engine Specifications

Engine Type:

Inline-six cylinder, four-stroke gasoline

Displacement:

2.8 Liters (2780 cc)

Bore X Stroke:

86.0 mm x 80.25 mm (typical for M110)

Compression Ratio:

8.0:1 or 8.7:1 (depending on specific variant and market)

Horsepower:

Approximately 177 hp (130 kW) at 5800 rpm (DIN) for the 280E variant with M110.981 engine

Torque:

Approximately 240 Nm (177 lb-ft) at 4000 rpm (DIN) for the 280E variant

Fuel Delivery:

Bosch K-Jetronic mechanical fuel injection

Fuel Type:

Unleaded gasoline (premium recommended)

Oil Capacity:

Approximately 6.5 - 7.0 liters with filter change (verify with specific manual data)

Coolant Type:

Antifreeze/coolant mixture (e.g., G05 or equivalent)

🔧 Transmission

Type:

4-speed automatic transmission (e.g., Mercedes-Benz 722.1)

Type:

4-speed manual transmission was also available on some W123 models, but the 280E typically came with automatic.

Fluid Type:

Dexron II (or equivalent ATF)

Fluid Capacity:

Approximately 6.0 - 7.0 liters (including torque converter, verify with specific manual)

📐 Dimensions

Length:

Approximately 4725 mm (186.0 in)

Width:

Approximately 1785 mm (70.3 in)

Height:

Approximately 1440 mm (56.7 in)

Curb Weight:

Approximately 1450-1550 kg (3200-3400 lbs), depending on equipment

Gross Vehicle Weight Rating:

Typically around 1950-2000 kg

🛡️ Safety Features

Crash Test Information:

While specific crash test ratings for the 1978 model in universally recognized formats like NCAP are rare, the W123 was engineered with a strong emphasis on safety for its era, featuring a robust passenger safety cell and crumple zones.

Brakes:

Four-wheel disc brakes (front ventilated), power assisted

Steering:

Recirculating ball power steering

Construction:

Reinforced passenger compartment, crumple zones, safety glass

Interior:

Energy-absorbing steering column, padded dashboard, seat belts (likely three-point front, two-point rear)

💡 Technology Features

Audio System:

Original equipment likely featured a basic AM/FM radio, potentially with cassette player in later production or optional upgrades. Speaker count and quality were typical for the era.

Cruise Control:

Optional on many models, providing basic speed regulation.

Climate Control:

Manual climate control with heating and ventilation. Optional automatic climate control was available on higher-spec models.

Connectivity Features:

No modern connectivity features (e.g., Bluetooth, USB, Apple CarPlay/Android Auto) were present from the factory.

🔧 Maintenance

Oil Change Interval:

Typically every 10,000 km (6,000 miles) or 12 months (verify with specific manual)

Major Service Interval:

Recommendations vary, but often involve spark plug replacement, valve adjustment, and more comprehensive inspections around 50,000-100,000 km

Engine Oil Spec:

API SG or higher, SAE 10W-40 or 15W-40 recommended (verify with manual for specific climate and engine condition)

Coolant Spec:

50/50 mix of Mercedes-Benz approved antifreeze (e.g., G05) and distilled water

Brake Fluid Spec:

DOT 3 or DOT 4

Common Problems 1:

Vacuum leaks in the central locking system, HVAC system actuators, and engine control components.

Common Problems 2:

Wear and tear on suspension bushings and ball joints, leading to steering looseness or clunking noises.

Common Problems 3:

Rust prone areas, especially around wheel arches, rocker panels, and jacking points. Underbody rust can also be a concern.

Common Problems 4:

Fuel distributor and injector seal issues with the K-Jetronic system can cause rough idling or poor performance.

Common Problems 5:

Electrical connectors and wiring can degrade over time, leading to intermittent faults.

Oil Filter:

Typical part numbers include Mann-Filter W917/1, Mahle OC 54, Bosch 0 451 103 072 (verify for specific engine)

Air Filter:

Typical part numbers include Mann-Filter C33202, Mahle LX 103 (verify for specific engine)

Fuel Filter:

Typical part numbers include Mann-Filter WK 31/1, Bosch 0 450 906 010 (verify for K-Jetronic system)

📚 Vehicle History

Mercedes Benz Legacy:

Mercedes-Benz has a long-standing reputation for building durable, high-quality, and technologically advanced vehicles, particularly in the luxury and executive car segments.

W123 Introduction:

The W123 chassis was introduced in 1976 as the successor to the W114/W115 models. It was renowned for its exceptional build quality, durability, and engineering robustness.

W123 Variants:

The W123 range included sedans (Saloon), coupes, estates (T-model), and limousines, powered by a variety of four and six-cylinder gasoline and diesel engines. The 280E was a prominent gasoline-powered model.

Production Years:

1976-1985

Manufacturing Locations:

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

Sales Figures:

Over 2.7 million units across all body styles were produced, making it one of Mercedes-Benz's most successful models.

🏆 Awards & Recognition

Industry Reputation:

The W123 is widely regarded as one of the most robust and reliable Mercedes-Benz models ever produced, often cited in automotive media for its longevity and build quality. Many examples are still in daily use decades later.

Collector Status:

Highly collectible and admired by enthusiasts for its classic styling, engineering, and driving experience.