🏷️ Basic Information

Make:

Mercedes-Benz

Model:

W126

Model Generation:

First Generation (1979-1991)

Body Style:

SE (Standard Wheelbase Sedan), SEL (Long Wheelbase Sedan), SEC (Coupe)

Chassis Code:

W126

👋 Introduction

Segment:

Full-size Luxury Sedan/Coupe

Key Competitors:

BMW 7 Series (E23/E32), Audi V8 Quattro, Jaguar XJ, Cadillac Fleetwood.

Design Philosophy:

Emphasized build quality, safety, comfort, and understated luxury. Introduction of advanced safety features and aerodynamic design principles for its era.

Distinctive Elements:

Iconic 'S-Class' styling, robust engineering, sophisticated ride quality, powerful straight-six and V8 engines, and available long-wheelbase (SEL) for increased rear passenger space.

📋 Manual Details

Vehicle Years Covered:

1979, 1980, 1981, 1982, 1983, 1984, 1985, 1986, 1987, 1988, 1989, 1990, 1991, 1992

Engine Variants Covered:

All W126 engine variants including M110, M116, and M117 in their various displacements and fuel injection configurations.

Total Pages:

5000+

Type:

Workshop Service Repair Manual

Language:

English

Format:

PDF

📖 Manual Coverage

Engine Management:

Detailed diagnostic, testing, and repair procedures for fuel injection (KE-Jetronic, K-Jetronic), ignition systems, emissions control.

Drivetrain:

Comprehensive coverage of automatic and manual transmissions, differential, driveshafts, and clutch (if applicable).

Suspension Steering:

Service, repair, and adjustment procedures for front and rear suspension, power steering system, including hydraulic components and steering gearbox.

Brakes:

Detailed instructions for hydraulic brake system, ABS (Anti-lock Braking System), brake disc/pad replacement, caliper service, and bleeding procedures.

Electrical Electronics:

Extensive coverage of wiring diagrams, fuse/relay identification, starter, alternator, battery, lighting systems, power windows, locks, mirrors, and climate control electronics.

Body Exterior:

Repair and adjustment of body panels, doors, hood, trunk, bumpers, glass, convertible top mechanisms (if applicable), and trim.

Body Interior:

Disassembly and reassembly of dashboard, seats, door panels, headliner, HVAC components, and interior trim.

Climate Control:

Service, diagnosis, and repair of air conditioning and heating systems, including refrigerant handling and component replacement.

Fuel System Details:

In-depth troubleshooting and repair of mechanical and electronic fuel injection systems, fuel pumps, fuel pressure regulators, injectors, and associated lines and sensors.

Exhaust System:

Information on catalytic converters, exhaust manifold, mufflers, and pipes, including diagnosis of leaks and component replacement.

Emission Control Systems:

Detailed procedures for diagnosing and servicing emissions control components, including secondary air injection, EGR (where applicable), and evaporative emission control systems.

Lighting And Signals:

Troubleshooting for headlights, taillights, turn signals, hazard lights, interior lighting, and related control modules.

Wiper Washer System:

Service and repair of wiper motor, linkage, wiper blades, and washer fluid pump and reservoir.

Routine Maintenance:

Oil changes, filter replacements, fluid checks and top-offs, lubrication points, spark plug replacement, and belt inspections.

Troubleshooting:

Systematic diagnostic procedures for common and complex issues, fault code interpretation (where applicable), and testing methods for various components.

Component Repair Rebuild:

Step-by-step instructions for removal, disassembly, inspection, repair, reassembly, and installation of virtually all major and minor vehicle components.

Adjustments Calibrations:

Detailed procedures for adjusting carburetors (early models), fuel injection systems, ignition timing, brake systems, parking brake, and suspension alignment parameters.

Technical Specifications:

Provides torque specifications, fluid capacities, electrical values, wear limits, and critical measurement data for all procedures.

Torque Specifications:

Extensive lists of torque values for all critical fasteners, ensuring proper assembly and preventing component damage.

Diagrams Illustrations:

Detailed exploded diagrams, wiring schematics, and photographic illustrations to guide users through repair processes.

Depth Of Coverage:

Comprehensive, bumper-to-bumper coverage suitable for professional technicians and advanced DIY enthusiasts. Includes detailed explanations and pictorial diagrams for complex tasks.

Diagnostic Procedures:

Focus on systematic fault diagnosis, including step-by-step guides for identifying issues within various vehicle systems.

Special Tools:

References to specific Mercedes-Benz special service tools required for certain operations, with explanations of their usage.

Cooling System:

Radiator, water pump, thermostat, coolant hoses, expansion tank, and fan clutch service and replacement procedures.

📊 Manual Specifications

Format:

PDF

Printability:

Yes, all pages are printable for convenient workshop use.

Binding:

Digital (PDF)

Digital Medium:

Downloadable PDF

Viewer:

Adobe Reader

Operating Systems:

Windows, macOS, Linux

⚙️ Engine Specifications

Engine Options:

M110 (2.8L I6), M116 (3.8L V8), M117 (4.2L V8, 5.0L V8, 5.6L V8)

Horsepower Range:

Approximately 155 hp (2.8L) to 240 hp (5.6L)

Torque Range:

Approximately 177 lb-ft (2.8L) to 330 lb-ft (5.6L)

Injection Systems:

Bosch K-Jetronic mechanical fuel injection (early models), Bosch KE-Jetronic electronic fuel injection (later models).

Ignition Type:

Electronic ignition with distributors.

Coolant Type:

Typically 50/50 mixture of Mercedes-Benz approved antifreeze and distilled water.

Engine Variants Detail:

2.8L M110 (DOHC I6), 3.8L M116 V8, 4.2L M117 V8, 5.0L M117 V8, 5.6L M117 V8 (later designated as 5.6L M117 E56).

🔧 Transmission

Standard Transmission:

4-speed automatic (e.g., 722.3)

Optional Transmission:

5-speed manual (rare, primarily on earlier European models).

Transmission Fluid:

MB 236.2, 236.3, or 236.6 spec ATF (Automatic Transmission Fluid), depending on specific transmission model and year.

📐 Dimensions

Length Sedan:

Approx. 197.1 inches (Standard) / 205.0 inches (SEL)

Width:

Approx. 70.5 inches

Height:

Approx. 56.1 inches

Curb Weight:

Approx. 3,600 - 4,000 lbs (depending on engine and body style)

Wheelbase Sedan:

Approx. 115.9 inches (Standard) / 123.4 inches (SEL)

🛡️ Safety Features

Era Safety Standards:

Designed to meet and exceed safety standards of its time, featuring crumple zones and robust safety cage construction.

Active Safety:

Anti-lock Braking System (ABS) became standard or optional depending on year and market. Power-assisted steering.

Passive Safety:

Driver and passenger airbags (introduced later in the production run), seatbelt pre-tensioners, reinforced doors, and impact-absorbing steering column.

💡 Technology Features

Audio Systems:

Factory-installed premium audio systems, often with cassette players. Some later models may have had CD changers as options.

Early Driver Aids:

Cruise control, power adjustable steering column, automatic climate control with recirculation mode.

Connectivity Features:

Limited by modern standards; primarily focused on in-car comfort and convenience features rather than external connectivity.

Climate Control Advancement:

Fully automatic climate control with temperature and air distribution regulation was a significant feature for its time.

🔧 Maintenance

Oil Change Interval:

Typically every 7,500 - 10,000 miles or 12 months, depending on driving conditions and oil specification used.

Transmission Service:

Fluid and filter change recommended typically every 30,000 - 50,000 miles.

Engine Coolant Service:

Flush and replace coolant every 2-3 years or 30,000-50,000 miles.

Engine Oil Spec:

API SG or higher, SAE 10W-40, 10W-50, or 20W-50 depending on climate. Refer to manual for precise MB approvals.

Brake Fluid Spec:

DOT 3 or DOT 4 approved brake fluid.

Coolant Capacity:

Approx. 8-10 liters (depending on engine size).

Power Steering Fluid Spec:

MB 236.3 approved hydraulic fluid or equivalent.

Common Faults:

Vacuum leaks in the central locking/climate control system, aging wiring harnesses, climate control blower motor resistor failure, self-leveling suspension issues (if equipped), fuel distributor issues (K-Jetronic), starter contact failure.

Common Wear Items:

Ball joints, tie rod ends, wheel bearings, exhaust system components, and shock absorbers/struts.

Key Maintenance Parts:

Fuel filters, air filters, oil filters, spark plugs, distributor caps and rotors, ignition wires, coolant hoses, drive belts, vacuum lines.

📚 Vehicle History

Mercedes Benz Legacy:

Continuation of Mercedes-Benz's reputation for engineering excellence, luxury, and safety, building upon the success of the W116 S-Class predecessor.

W126 Development:

Introduced in 1979 as the second generation S-Class, it marked a significant step forward in aerodynamics, safety, and interior comfort. Received styling and technical updates throughout its production life, including engine displacements and feature enhancements.

Production Years:

1979-1991

Manufacturing Sites:

Sindelfingen, Germany.

🏆 Awards & Recognition

Industry Acclaim:

Widely praised for its engineering, safety, and comfort upon release. Considered a benchmark for luxury sedans of the 1980s.