Value Proposition:
Provides essential, dealership-grade technical information for owners and independent mechanics, enabling accurate maintenance, diagnosis, and repair of the 1978 R107/C107 SL-Class.
Uniqueness:
This is not generic information; it is vehicle-specific factory data, identical to what professional technicians use, covering all repairs A-Z for the 1978 models.
Digital Benefits:
Searchable PDF, printable pages, easy navigation, ability to zoom into diagrams, no physical wear and tear on original documents.
Engine:
Detailed diagnostics, repair, overhaul, timing, fuel delivery, emission control systems (e.g., D-Jetronic injection for applicable engines).
Transmission:
Automatic and Manual transmission service, repair, adjustment, and fluid specifications.
Brakes:
Hydraulic system, calipers, master cylinder, vacuum booster, parking brake, ABS (if equipped for the model year).
Suspension And Steering:
Front and rear suspension components, shock absorbers, springs, control arms, power steering system, steering gear, wheel alignment specifications.
Electrical System:
Wiring schematics, battery, charging system (alternator, regulator), starting system, lighting, gauges, instruments, power windows, central locking, cruise control.
Body And Chassis:
Body panel repair, door mechanisms, hood, trunk, convertible top operation (if applicable), glass, mirrors, interior trim, seats.
Climate Control:
Air conditioning system service, refrigerant handling, heater core, blower motor, climate control panel diagnostics.
Routine Maintenance:
Oil changes, filter replacements, spark plug checks, belt adjustments, fluid level checks and top-offs, lubrication points.
Troubleshooting:
Diagnostic procedures for common and uncommon faults across all systems, symptom-based troubleshooting guides.
Component Overhaul:
Detailed step-by-step instructions for rebuilding engines, transmissions, brake calipers, steering gears, etc.
Diagnostics:
Testing procedures for electrical components, fuel system pressure testing, ignition timing adjustments.
Depth:
Factory-level, covering everything from basic fluid checks to complete engine and transmission rebuilds, including intricate electrical diagnostics and wiring schematics.
Primary Engine Options 1978
Engine Code 1:
M110 (2.8L Inline-6, DOHC) - Primarily for C107 280SLC, and some R107 280SL in certain markets.
Engine Code 2:
M117 (3.5L V8, SOHC) - Commonly found in R107 350SL.
Engine Code 3:
M116 (4.5L V8, SOHC) - Found in R107 450SL and 450SLC.
Power Delivery:
Smooth, torquey delivery characteristic of Mercedes-Benz engineering of the era. Precise specifications (HP/Torque) would be engine-specific and found within the manual.
Fuel Injection Type:
Bosch D-Jetronic (Electronic Fuel Injection) for most models, or mechanical fuel injection systems for some carbureted variants in specific markets. Carburetor specifications would also be covered if applicable.
Oil Change Interval:
Typically every 7,500 miles or 12,000 km, or annually, whichever comes first. Specific oil type and viscosity (e.g., API SG or higher, SAE 20W-50 or 10W-40 depending on climate) detailed in manual.
Coolant Type:
Ethylene glycol based coolant, typically a 50/50 mix with distilled water. Specific Mercedes-Benz approved coolant types would be listed.
Engine Oil Capacity:
Varies by engine: ~6.5-7.5 liters for M117/M116 V8s, ~7.0 liters for M110 Inline-6. Exact capacities are in the manual.
Type:
Automatic Transmission (e.g., 3-speed or 4-speed automatic) was standard on most models, especially V8 variants. Manual transmissions were less common but available on some 6-cylinder models.
Type:
4-speed Manual Transmission (often available as an option on 6-cylinder models).
Automatic Features:
Torque converter, hydraulic control, gear selection linkage.
Automatic Transmission Fluid:
Type A, Type A Suffix A, or Dexron II specified for the automatic transmissions of this era. Manual transmission fluid specifications also detailed.
Historical Safety:
The R107/C107 chassis was known for its robust construction and safety features for its era, including crumple zones and a strong safety cell. Modern safety rating equivalents are not directly applicable but it performed well for its time.
Braking System:
Four-wheel disc brakes, power-assisted with vacuum booster. Anti-lock Braking System (ABS) was introduced later in the R107's life cycle, so its presence in a 1978 model would be model-specific and rare.
Occupant Protection:
Three-point seatbelts (often retractable), padded dashboard and steering wheel, impact-absorbing steering column.
Audio System:
Period-appropriate AM/FM radio, often with cassette player. Speaker locations and wiring diagrams are covered.
Cruise Control:
Optional feature on many models, with diagnostic and repair procedures detailed for its vacuum or electronic control systems.
Electrical Systems:
Emphasis on robust, analog electrical systems. No modern CAN bus or multiplexing. Wiring schematics are critical for diagnosis.
Tune Up Frequency:
Recommended annually or every 15,000 miles (24,000 km), focusing on ignition system checks (plugs, points, condenser), fuel filter, and air filter replacement.
Timing Belt Chain:
Engines utilize timing chains, which are designed for the life of the engine but require periodic checks for tension and wear, as detailed in the manual.
Brake Fluid Type:
DOT 3 or DOT 4 glycol-based brake fluid. Regular flushing and replacement are critical for brake system longevity.
Power Steering Fluid:
Specific hydraulic fluid or ATF as specified by Mercedes-Benz for the power steering system. Refer to manual for exact type and capacity.
Common Problems 1978 Models:
Rust in common areas (wheel wells, rocker panels, window frames), fuel distributor/accumulator issues on D-Jetronic systems, vacuum leaks, aging rubber components (hoses, mounts), differential seals, climate control blend door actuators.
Example Oil Filter P N:
While specific part numbers change and many aftermarket equivalents exist, a typical Mann filter for a M117 V8 might be W919/2 or equivalent. The manual would reference the OEM number or provide guidance.
Mercedes Benz Legacy:
Mercedes-Benz has a long-standing reputation for building durable, luxurious, and technologically advanced vehicles. The SL-Class is their flagship roadster line, known for performance and comfort.
R107 C107 Development:
The R107/C107 replaced the W113 'Pagoda' SL and was in production for 18 years (1971-1989), making it one of Mercedes-Benz's longest-running chassis. The 1978 models represent a mature iteration of this design, with refinements over earlier years.
Manufacturing Location:
Germany
