🏷️ Basic Information

Make:

Mercedes-Benz

Model:

W123 E-Class

Year:

1977

Chassis Code:

W123

Model Designation:

E

👋 Introduction

Positioning:

The W123 E-Class was a benchmark for German engineering, comfort, and durability, representing Mercedes-Benz's commitment to building robust, long-lasting vehicles in the luxury sedan market.

Competitors:

Competed directly with luxury sedans from BMW (e.g., E21 3 Series, E12 5 Series), Audi (e.g., Audi 100), and American luxury marques, often outperforming them in build quality and longevity.

Vehicle Attributes:

Renowned for its build quality, ride comfort, safety features for its era, and the availability of efficient diesel engines. Offered in sedan, coupe, and wagon (T-model) body styles.

📋 Manual Details

Coverage:

All W123 E-Class models and all repairs A-Z

Pages:

Estimated 1000+

Type:

Official Factory Service and Repair Manual

Language:

English

Format:

Print (Original or High-Quality Reproduction)

📖 Manual Coverage

Engine:

Detailed diagnostics, repair, and overhaul for all gasoline and diesel engines (e.g., M110, M115, OM615, OM616, OM617)

Transmission:

Service and repair for manual and automatic transmissions (e.g., 4-speed, 5-speed manual; 3-speed, 4-speed automatic)

Fuel System:

Carburetor (Zenith, Solex) and fuel injection (Bosch K-Jetronic) system servicing, troubleshooting, and adjustment

Electrical System:

Complete electrical schematics, troubleshooting guides, starter, alternator, ignition system, lighting, and accessory repair

Brakes:

Hydraulic system, disc and drum brake overhaul, power assist (Bosch-Mitte) service, parking brake

Suspension Steering:

Front and rear suspension components, steering box, power steering system, wheel alignment

Body Chassis:

Body panel removal and installation, interior trim, door mechanisms, glass replacement, chassis lubrication

Heating Ventilation Air Conditioning:

HVAC system diagnostics, repair, and refrigerant handling (where applicable)

Routine Maintenance:

Oil changes, filter replacements, tune-ups, fluid checks and changes, belt adjustments

Engine Repair:

Complete engine rebuild procedures, cylinder head removal and installation, piston and ring replacement, camshaft timing

Transmission Repair:

Clutch replacement, transmission overhaul, torque converter service, shift linkage adjustment

Brake System Repair:

Brake pad/shoe replacement, caliper and wheel cylinder overhaul, brake line replacement, bleeding procedures

Suspension Steering Repair:

Ball joint, tie rod, control arm, shock absorber replacement, steering box adjustment/rebuild

Electrical Troubleshooting:

Diagnostic flowcharts for common electrical faults, component testing procedures

Special Tools:

Identification and usage of specialized Mercedes-Benz tools required for specific repairs

Depth:

Comprehensive from basic maintenance to complete component overhaul and rebuilding, including detailed diagnostic procedures

📊 Manual Specifications

Digital Format:

N/A (physical print manual)

Quality:

High-resolution reproduction of original factory documentation, clear diagrams and text

Binding:

Perfect bound or spiral bound for lay-flat usability

Paper:

Durable, high-quality paper stock suitable for workshop environments

⚙️ Engine Specifications

Engine Options:

Multiple 4-cylinder and 5-cylinder gasoline (M110 2.8L, M115 2.0L/2.3L) and diesel (OM615 2.0L/2.2L, OM616 2.4L, OM617 3.0L) engines

Typical Hp:

Gasoline: 115-145 hp (depending on engine and market); Diesel: 70-88 hp (depending on engine)

Gasoline Injection Type:

Bosch K-Jetronic mechanical fuel injection on many models

Diesel Injection Type:

Bosch inline injection pump

Coolant Type:

Glycol-based antifreeze (e.g., Mercedes-Benz Specification 325.0 or equivalent)

Oil Type:

API SG/CD or higher, viscosity SAE 10W-40 or 15W-40 recommended (refer to manual for specific engine requirements)

Oil Capacity:

Typically 6.5 - 8.0 liters (6.9 - 8.5 US quarts) with filter, depending on engine

🔧 Transmission

Transmission Options:

4-speed manual, 4-speed automatic (optional on most models)

Transmission Options 2:

5-speed manual (introduced later in the W123 lifecycle, but manual transmission service is covered)

Automatic Transmission Type:

3-speed (e.g., 722.1) or 4-speed (e.g., 722.3) automatic transmission, depending on model and year

Automatic Transmission Fluid:

Dexron III/Mercon compatible or MB Specification 236.1

Manual Transmission Fluid:

API GL-4 gear oil, SAE 75W-90 or 80W-90

📐 Dimensions

Wheelbase Sedan:

Approx. 2795 mm (110.0 inches)

Length Sedan:

Approx. 4725 mm (186.0 inches)

Width Sedan:

Approx. 1790 mm (70.5 inches)

Height Sedan:

Approx. 1435 mm (56.5 inches)

Curb Weight:

Varies by engine and equipment, typically 1400-1600 kg (3086-3527 lbs)

Gross Vehicle Weight Rating:

Varies by model, typically around 2000 kg (4409 lbs)

Trunk Volume Sedan:

Substantial, designed for touring, specific volume not readily available without manual reference

🛡️ Safety Features

Era Safety Features:

Designed with safety as a priority for its era; features include a strong safety cage, crumple zones, padded interior, and safety belts. ABS was not standard or commonly available in 1977.

Braking System:

Front and rear disc brakes (ventilated fronts), dual-circuit hydraulic system

Seatbelts:

Standard front seat belts, optional rear seat belts

Steering Column:

Collapsible steering column for improved impact protection

💡 Technology Features

Audio System:

Factory fitted AM/FM radio with cassette player common, though many were upgraded over time.

Cruise Control:

Optional cruise control available on some models

Era Technology:

Focus on mechanical and electrical reliability rather than digital connectivity. Features like power windows, central locking, and air conditioning were often optional extras.

🔧 Maintenance

Oil Change Interval:

Typically every 10,000-15,000 km (6,000-10,000 miles) or annually, refer to manual for specific engine/oil type.

Air Filter Replacement:

Every 20,000-30,000 km (12,000-18,000 miles) or as needed based on operating conditions.

Fuel Filter Replacement Diesel:

Regular replacement of diesel fuel filter is critical for engine longevity.

Brake Fluid:

DOT 3 or DOT 4 brake fluid

Power Steering Fluid:

ATF Dexron II or equivalent

Coolant Capacity:

Approx. 7.0-8.5 liters (7.4-9.0 US quarts), depending on engine and radiator size

Common Wear Items:

Vacuum system leaks (climate control, central locking), rust (especially around wheel arches, jacking points, door bottoms), aging rubber components (bushings, hoses), early diesel engine glow plug issues.

Engine Specific Concerns:

M110 engine timing chain stretching, OM617 vacuum shutoff valve failures, K-Jetronic system adjustments.

📚 Vehicle History

Mercedes Benz Legacy:

Mercedes-Benz has a long-standing reputation for engineering excellence, safety, and luxury vehicles dating back to the early 20th century.

W123 Introduction:

The W123 chassis replaced the W114/W115 ('Stroke Eight') series and was produced from 1976 to 1985. It solidified Mercedes-Benz's reputation for robust build quality and reliability.

Production Years:

1976-1985

Manufacturing Locations:

Primarily Germany, with assembly also occurring in other international locations.

🏆 Awards & Recognition

Industry Acclaim:

The W123 chassis consistently received praise from automotive journalists and owners for its exceptional durability, comfort, and perceived quality, earning it a reputation as one of the best-built cars of its era.

Longevity Awards:

Often cited in lists of longest-lasting vehicles, with many W123s exceeding 500,000 miles (800,000 km) with proper maintenance.