🏷️ Basic Information

Make:

Mercedes-Benz

Model:

W123 280E

Chassis Code:

W123

Engine Code:

M110 (for 280E)

Generation Code:

First Generation W123

Body Styles Available In W123 Range:

Sedan (Saloon), Estate (Station Wagon/T-Model), Coupe, Long Wheelbase Sedan

👋 Introduction

Target Audience:

DIY enthusiasts and experienced professional mechanics working on Mercedes-Benz W123 280E.

Value Proposition:

Cost-effective alternative to dealership service, enabling owners to maintain their vehicles themselves.

Comparison To Oem Manuals:

Provides equivalent technical depth and procedural guidance as official Mercedes-Benz workshop manuals of the era.

Structured Instructions:

Numbered, step-by-step instructions with detailed substeps for clarity.

Safety Information:

Includes notes, cautions, and warnings to highlight critical safety and procedural points.

Visual Guidance:

Utilizes hundreds of photos, illustrations, and enlarged insets for detailed part identification and procedure visualization.

Navigation:

Numbered table of contents for quick and easy access to specific repair information.

📋 Manual Details

Primary Coverage:

Service and Repair for Mercedes-Benz W123 280E

Secondary Coverage Potential:

May include relevant information for other W123 gasoline models with similar M110 engine variants.

Estimated Page Count:

Refer to actual manual for precise count, but typically comprehensive repair manuals of this era exceed 500 pages.

Type:

Service and Repair Manual

Language:

English

Digital Format:

PDF

Compatibility:

All Versions of Windows & Mac

Software Requirements:

Adobe PDF Reader & WinZip

📖 Manual Coverage

Engine Mechanical:

Engine assembly, disassembly, cylinder head, pistons, crankshaft, camshafts, timing system, lubrication system.

Fuel System:

Fuel injection system (Bosch K-Jetronic), fuel pump, fuel filter, fuel lines, injectors, cold start system.

Ignition System:

Distributor, ignition coil, spark plugs, high-tension leads, ignition timing.

Cooling System:

Radiator, water pump, thermostat, cooling fan, coolant hoses, heater core.

Exhaust System:

Exhaust manifolds, catalytic converter (if applicable for market/year), muffler, exhaust pipes.

Transmission Manual:

Gearbox overhaul, clutch system, shift linkage, lubrication.

Transmission Automatic:

Overhaul of the automatic transmission (e.g., 4-speed or 5-speed), hydraulic control, torque converter, transmission fluid.

Drivetrain:

Driveshaft, universal joints, differential, rear axle assembly.

Suspension Front:

Control arms, ball joints, shock absorbers, springs, steering knuckles.

Suspension Rear:

Independent rear suspension components, trailing arms, shock absorbers, springs, sway bar.

Steering:

Steering box, power steering pump, steering column, tie rods, steering linkage.

Brakes Front:

Brake calipers, brake discs, brake pads, brake lines.

Brakes Rear:

Brake calipers/drums, brake discs/drums, brake pads/shoes, brake lines, parking brake mechanism.

Electrical System Charging:

Alternator, voltage regulator, battery, wiring.

Electrical System Starting:

Starter motor, ignition switch, neutral safety switch.

Electrical System Lighting:

Headlights, taillights, interior lights, turn signals, fuses, relays.

Electrical System Accessories:

Wipers, horn, power windows, power locks, radio, climate control components.

Body And Chassis:

Body panel repair, corrosion protection, structural components, door mechanisms, glass replacement.

Climate Control:

HVAC system, heater core, blower motor, air conditioning (if equipped), refrigerant system.

Preventive Maintenance:

Oil changes, filter replacements, fluid checks and changes, spark plug replacement, belt inspections, brake checks.

Troubleshooting:

Diagnosis and repair of common and uncommon problems across all major systems, including electrical and fuel injection.

Engine Rebuild:

Complete disassembly, inspection, measurement, and reassembly procedures for the M110 engine.

Transmission Overhaul:

Detailed steps for dismantling, repairing, and reassembling both manual and automatic transmissions.

Brake System Repair:

Replacement of pads, discs, hoses, caliper rebuilds, bleeding procedures.

Electrical Component Repair:

Testing and replacement of starters, alternators, fuel pumps, wiring harness repairs.

Suspension And Steering Repair:

Replacement of wear items like ball joints, tie rods, bushings, shock absorbers, and steering components.

Fuel Injection System Diagnosis:

Troubleshooting and adjustment of the K-Jetronic system, including air flow meter, warm-up regulator, and injectors.

Bodywork And Trim Removal:

Instructions for removing and reinstalling interior and exterior trim panels, bumpers, and doors.

Depth Of Information:

Comprehensive, from basic maintenance to complete engine and transmission rebuilds.

Diagnostic Capabilities:

Detailed troubleshooting guides and electrical diagrams for diagnosing issues.

Illustrations And Diagrams:

Hundreds of photos, illustrations, and detailed wiring diagrams to aid comprehension.

Component Level Detail:

Focuses on individual component testing, repair, and replacement.

📊 Manual Specifications

Digital Format:

PDF

Searchability:

Likely text-searchable PDF, enabling quick information retrieval.

Printability:

All pages are printable, allowing for use in a workshop environment.

Digital Binding:

N/A (Digital Download)

Digital Paper:

N/A (Digital Download)

⚙️ Engine Specifications

Engine Type:

Inline 6-cylinder, SOHC (Single Overhead Camshaft)

Engine Displacement:

2.8 Liters (2799 cc)

Engine Code Designation:

M110.984 (typically for W123 280E)

Horsepower Approximate:

185 PS (approx. 182 bhp or 136 kW) at around 5800 rpm (may vary slightly by market and year).

Torque Approximate:

240 Nm (approx. 177 lb-ft) at around 4000 rpm (may vary slightly by market and year).

Fuel Delivery:

Bosch Continuous Injection System (CIS), commonly known as K-Jetronic.

Fuel Type:

Unleaded Gasoline (Premium)

Bore X Stroke:

86.0 mm x 80.25 mm (approximate, refer to manual for exact figures).

Compression Ratio:

8.0:1 or 8.7:1 (depending on variant and market, typically 8.0:1 for many 280E).

🔧 Transmission

Transmission Type:

4-speed manual transmission (optional, but less common than automatic for this engine in many markets).

Transmission Type:

4-speed or 5-speed automatic transmission (most common for the 280E).

Automatic Transmission Control:

Hydraulically controlled, with torque converter. May include sport/economy modes.

Automatic Transmission Fluid:

Refer to manual for specific MB approval (e.g., MB 236.2 or similar DEXRON/MERCON types compatible at the time).

Automatic Transmission Fluid Capacity:

Approximately 7-9 liters for a complete fluid change (including torque converter, refer to manual for exact amount).

📐 Dimensions

Body Style:

Sedan (4-door)

Wheelbase:

2810 mm (110.6 inches)

Overall Length:

4725 mm (186.0 inches)

Overall Width:

1785 mm (70.3 inches)

Overall Height:

1430 mm (56.3 inches)

Curb Weight Approximate:

1400 - 1550 kg (3086 - 3417 lbs), depending on transmission and equipment.

Gross Vehicle Weight Rating:

Refer to vehicle data plate; typically around 1950-2050 kg.

Towing Capacity:

Not typically specified for this model; generally not recommended for significant towing.

🛡️ Safety Features

Crash Test Data Availability:

Limited modern official crash test data available for this era; focus on structural integrity typical of Mercedes-Benz engineering.

Braking System:

Four-wheel disc brakes (front ventilated) with power assistance. Anti-lock Braking System (ABS) was optional on later models.

Steering System:

Recirculating ball steering with power assist (standard).

Occupant Protection:

Reinforced safety cell, energy-absorbing steering column, padded dashboard and interior surfaces.

Seat Belts:

Three-point inertia-reel seat belts in the front, lap belts in the rear (front belts may have been optional or an early type in some very early models).

💡 Technology Features

Audio System:

Factory-installed AM/FM radio and cassette player (optional), with potential for dealer-fitted upgrades or aftermarket replacements.

ABS Availability:

Anti-lock Braking System (ABS) was an optional feature, often appearing on later production models.

Original Connectivity:

Limited to basic vehicle functions and factory radio/antenna system. No modern connectivity features like Bluetooth or USB.

Power Options:

Optional power windows, power door locks, power steering, cruise control (on some models), and air conditioning were available, contributing to its premium feel.

🔧 Maintenance

Oil Change Interval:

Typically every 10,000 - 15,000 km or 12 months, whichever comes first (refer to manual for specific recommendation for the 280E).

Filter Replacement Interval:

Oil filter with every oil change. Air filter and fuel filter typically every 20,000 - 30,000 km.

Spark Plug Replacement Interval:

Approximately every 20,000 - 40,000 km, depending on type (e.g., standard vs. platinum).

Transmission Fluid Service:

Automatic transmission fluid and filter typically recommended every 40,000 - 60,000 km for optimal performance and longevity.

Engine Oil Specification:

Refer to manual for specific viscosity (e.g., 10W-40, 15W-40, or 20W-50) and API service classification (e.g., SE, SF, SG).

Engine Oil Capacity:

Approximately 7.5 liters (including filter) for the M110 engine (refer to manual for exact capacity).

Coolant Specification:

Ethylene glycol-based antifreeze mixture (50/50 with distilled water).

Brake Fluid Specification:

DOT 3 or DOT 4 brake fluid.

Common W123 Issues:

Rust (especially around wheel arches, sills, and sunroof), vacuum leaks in the central locking and climate control systems, aging rubber components (hoses, mounts), potential wear on K-Jetronic system components, and differential seals.

M110 Engine Specifics:

Timing chain stretch over high mileage, potential for injector seal leaks, and proper adjustment of the K-Jetronic system is critical for smooth operation.

📚 Vehicle History

Mercedes Benz Legacy:

Mercedes-Benz is renowned for its engineering excellence, durability, and pioneering safety features dating back to the invention of the automobile.

W123 Introduction:

The W123 series was introduced in 1975, succeeding the W114/W115 series. It was designed to be exceptionally robust and durable.

280E Positioning:

The 280E, with its larger M110 engine, represented the higher end of the W123 sedan range, offering more power and refinement.

Production Years For W123:

1975-1985 (Sedan and Coupe), 1977-1985 (Estate/T-Model).

Global Sales Success:

The W123 was a massive commercial success, with over 2.7 million units produced across all body styles, solidifying Mercedes-Benz's reputation for build quality.

🏆 Awards & Recognition

General Accolades:

The W123 series is widely recognized by automotive journalists and enthusiasts as one of the most durable and over-engineered cars ever produced by Mercedes-Benz, earning it a reputation as a true 'modern classic'.

Reliability Reputation:

Exceptionally high reliability and longevity, often cited as a benchmark for build quality and engineering.

Industry Standard Compliance:

Designed and manufactured to meet all relevant German and international automotive safety and emissions standards of its production era.