Historical Context:
The Mercedes-Benz W114/W115 series, often referred to as the 'New Generation' sedans and coupes, represented a significant evolution for the brand. They were positioned as executive-class vehicles, offering a blend of comfort, durability, and engineering excellence that defined Mercedes-Benz vehicles of that era. This manual caters to owners and technicians who appreciate and maintain these robust and elegantly designed automobiles.
Target Audience:
Enthusiasts, classic car owners, independent repair shops, and DIY mechanics specializing in or maintaining vintage Mercedes-Benz vehicles.
Competitors:
Competed with vehicles like the BMW E3, BMW E9, Jaguar XJ, Volvo 140/164, and American luxury sedans of the period.
Manual Value Proposition:
This manual provides comprehensive, dealership-level information, enabling owners to perform detailed maintenance and repairs, saving costs and preserving the vehicle's integrity. It includes specialized procedures and torque specifications crucial for maintaining the quality and performance expected of a Mercedes-Benz.
Engine:
Complete overhaul, diagnostics, tuning, fuel injection/carburetion, lubrication, cooling systems
Transmission:
Manual and automatic transmission repair, overhaul, fluid services, adjustments
Electrical System:
Wiring diagrams, component testing, charging system, starting system, lighting, instruments
Fuel System:
Fuel pumps, fuel lines, fuel filters, fuel injection systems (Bosch), carburetors
Ignition System:
Distributor, ignition coils, spark plugs, timing
Brake System:
Hydraulic system, disc and drum brake service, parking brake, fluid specifications
Suspension:
Front and rear suspension components, shock absorbers, springs, bushings
Steering:
Steering box, tie rods, power steering system
Exhaust System:
Exhaust manifolds, pipes, mufflers, catalytic converter (later models)
Body And Chassis:
Body panel repair, doors, windows, interior trim, chassis components
Climate Control:
Heating system operation, blower motor, defrost system, optional air conditioning (diagnostics and service)
Interior:
Seat removal and installation, dashboard disassembly, door panel removal, headliner service
Exterior:
Door mechanism repair, window regulator service, trunk and hood operation, chrome trim replacement
Wheels And Tires:
Wheel bearing service, tire pressure recommendations, wheel alignment procedures.
Maintenance:
Routine servicing, oil changes, filter replacements, fluid checks, lubrication schedules
Diagnostics:
Troubleshooting guides, fault diagnosis for various systems, diagnostic codes
Repair:
Step-by-step repair instructions for all major components and systems
Overhaul:
Detailed procedures for complete engine, transmission, and component overhauls
Installation:
Removal and installation procedures for various parts and assemblies
Tune Ups:
Engine tuning, carburetor adjustment, ignition timing
Engine Rebuild:
Detailed step-by-step instructions for dismantling, inspecting, machining, and reassembling engines, including piston ring installation, bearing replacement, and crankshaft balancing.
Transmission Rebuild:
Comprehensive guides for both manual and automatic transmissions, covering gear synchronization, clutch pack replacement, valve body diagnostics, and torque converter overhaul.
Wiring Diagrams:
Detailed electrical schematics for all vehicle systems, including engine management, lighting, instrumentation, and optional accessories.
Troubleshooting Charts:
Systematic diagnostic flowcharts to identify and resolve common problems efficiently.
Depth:
Comprehensive; covers everything from basic maintenance to complete engine and transmission rebuilds, suitable for professional technicians and experienced DIYers.
W114 Engine Options:
M114 (2.3L Inline-6, e.g., 230), M115 (2.0L Inline-4, e.g., 200), M115 (2.2L Inline-4 Diesel, e.g., 220 D), M116 (2.8L V8 - rare, later models)
W115 Engine Options:
M115 (2.0L Inline-4, e.g., 200), M115 (2.2L Inline-4 Diesel, e.g., 220 D), M115 (2.4L Inline-4 Diesel, e.g., 240 D)
Typical Horsepower Range:
Approximately 90 hp (diesel) to 130 hp (petrol inline-6)
Typical Torque Range:
Approximately 140 Nm to 185 Nm
Fuel Delivery W114:
Bosch D-Jetronic fuel injection (for most 6-cylinder models) or Solex/Zenith carburetors
Fuel Delivery W115:
Solex/Zenith carburetors (petrol models), Bosch inline fuel injection pumps (diesel models)
Construction:
Inline-4 and Inline-6 cylinder configurations, cast iron block, aluminum cylinder head.
Historical Safety Standards:
Designed to meet safety standards of its era, incorporating crumple zones and safety cell construction. Specific crash ratings as per modern standards are not directly applicable but it was considered a safe vehicle for its time.
Braking System:
Front disc brakes, rear drum brakes (power assisted)
Steering System:
Recirculating ball steering, optional power steering
Seat Belts:
Standard front seat belts, optional rear seat belts
Body Structure:
Integrated safety cage, energy-absorbing steering column
Oil Change Interval:
Typically every 5,000-10,000 km (3,000-6,000 miles) or 6-12 months, depending on driving conditions and oil type.
Tune Up Interval:
Recommended annually or every 15,000-20,000 km (9,000-12,000 miles) for ignition system and carburetor adjustments.
Engine Oil Specification:
API SF/CD or higher, SAE 10W-40 or 15W-40 (or as specified in manual based on climate). Check manual for exact MB specifications.
Coolant Specification:
Ethylene glycol-based coolant mixed with distilled water (50/50 ratio). Specific MB coolant types should be verified.
Transmission Fluid Automatic:
Dexron II or equivalent. Capacity approximately 1.5-2.5 liters for torque converter refill. Manual transmissions use gear oil (e.g., SAE 80W-90).
Brake Fluid Specification:
DOT 3 or DOT 4 hydraulic brake fluid. Check manual for specific Mercedes-Benz approval.
Common Wear Items:
Rubber bushings (suspension, exhaust mounts), vacuum lines, distributor points/condenser (if not electronic ignition), fuel lines, oil leaks (especially from oil pan and valve cover gaskets), aging wiring harnesses.
Diesel Specific:
Glow plug system reliability, injector pump calibration, exhaust manifold cracking (less common but possible).
Cooling System:
Radiator leaks, water pump failure, thermostat sticking.
Fuel System:
Carburetor float bowl issues, fuel pump diaphram fatigue, clogged fuel filters, aging fuel lines that can degrade from modern fuel additives.
Valve Lash Adjustment:
Requires periodic adjustment on some engine variants. Cold valve lash specifications are critical and provided in the manual.
Torque Specifications:
The manual includes critical torque specifications for cylinder head bolts, main bearings, connecting rods, wheel hubs, etc., essential for proper engine and chassis assembly.
Timing Belt Chain:
Engines use timing chains, which are generally durable but require periodic inspection for stretch and tensioner wear. Specific inspection intervals are detailed in the manual.
Mercedes Benz Philosophy:
Mercedes-Benz has a long-standing reputation for engineering excellence, durability, and safety. The W114/W115 embodied this by offering a robust chassis, reliable powertrains, and a focus on passenger comfort and long-term usability.
W114 W115 Introduction:
Introduced in 1968 (initially as W114/W115), these models replaced the W110 'Fintail' series. They were designed by Paul Bracq and brought a more modern, cleaner aesthetic to Mercedes-Benz sedans.
Facelift And Updates:
Received a significant facelift in 1973, introducing larger bumpers, revised grille, and updated interior features. Engine options also evolved, including the introduction of the 2.5L M114 and 2.8L M116 V8 in some variants.
Body Styles:
Available as a 4-door sedan (Saloon) and a 2-door coupe.
Production Period:
1968-1976
Production Volume:
Over 1.9 million units produced across all variants, making it a very successful model for Mercedes-Benz.
