Segment:
Luxury Grand Tourer (GT) Convertible
Target Audience:
Enthusiasts and owners seeking in-depth technical knowledge for maintenance and repair
Competitors 1990S:
BMW 8 Series Convertible, Jaguar XJS, Porsche 911 Targa/Cabriolet
Vehicle Identity:
Flagship luxury convertible, blend of performance and comfort, iconic Mercedes-Benz engineering
Manual Value Proposition:
Empowers owners and independent mechanics with factory-level diagnostic and repair information, crucial for preserving the value and functionality of a classic Mercedes-Benz
Engine Mechanical:
Full disassembly, assembly, timing, lubrication, cooling, fuel injection (Bosch KE-Jetronic)
Engine Electrical:
Ignition system, starter, alternator, engine control unit (ECU) diagnostics and wiring diagrams
Transmission:
4-speed automatic transmission (722.3xx series), hydraulic system, shifting characteristics, repair procedures
Suspension:
Front and rear suspension components, shock absorbers, springs, bushings, hydraulic systems (e.g., self-leveling rear axle if equipped on some variations)
Brakes:
Hydraulic system, ABS (Anti-lock Braking System), brake discs, pads, calipers, bleeding procedures
Steering:
Power steering system, steering column, steering rack, troubleshooting
Body:
Body panels, doors, hood, trunk, convertible top mechanism (hydraulics, operation), interior trim, glass
Electrical System:
Lighting, wipers, horn, power windows, power seats, climate control, central locking, diagnostic codes and wiring diagrams
Climate Control:
Air conditioning system (compressor, condenser, evaporator), heating system, blower motor, HVAC controls
Maintenance:
Oil changes, filter replacements, fluid checks and changes, spark plug replacement, belt inspection and replacement, lubrication points
Troubleshooting:
Diagnosis of common issues, diagnostic trouble codes (DTCs), electrical fault finding, mechanical component diagnosis
Repair:
Detailed step-by-step repair instructions for all major mechanical and electrical components, including rebuild procedures for specific units
Installation:
Guidance on installing replacement parts and components
Adjustments:
Setting ignition timing, idle speed adjustment, brake adjustments
Depth:
Comprehensive, covering basic to advanced diagnostics and complete overhaul procedures
Airbags:
Driver's side airbag (standard from 1990), Passenger airbag (optional/standard on later models within this range)
Rollover Protection:
Automatic rollover hoops that deploy in the event of a rollover.
Seatbelts:
Pre-tensioning seatbelts
ABS:
Standard Anti-lock Braking System (ABS)
NHTSA Ratings:
Not specifically rated by NHTSA for this era in the same way modern vehicles are; built to strict Mercedes-Benz safety standards of the time.
Radio System:
Factory-fitted cassette radio with optional CD changer. Basic analog controls.
Display:
Analog gauges for speed, RPM, temperature, and fuel. Warning lamps for system status.
Cruise Control:
Standard electronic cruise control.
Traction Control:
Often equipped with Acceleration Slip Regulation (ASR) in later models or as an option.
External Connectivity:
Limited to power antennas; no modern Bluetooth or USB connectivity from the factory.
Oil Change Interval:
Every 7,500-10,000 miles or 12 months, whichever comes first, depending on driving conditions.
Transmission Fluid Interval:
Recommended at 60,000-100,000 miles, or if fluid shows signs of degradation.
Coolant Change Interval:
Every 2-3 years or 30,000 miles.
Engine Oil Type:
API SG/SH or ACEA A2/A3, viscosity typically 10W-40 or 15W-50 depending on climate.
Coolant Type:
Mercedes-Benz approved coolant (e.g., G48 or equivalent) mixed at a 50/50 ratio with distilled water.
Brake Fluid Type:
DOT 4 low viscosity.
Wiring Harness:
Degradation of wiring harness insulation, particularly in the engine bay, due to age and heat.
Hydraulic Systems:
Leaks in convertible top hydraulics, suspension components, or power steering.
Engine Management Kejetronic:
Issues with the Air Flow Meter (AFM) sensor, fuel distributor, or control pressure regulator can cause drivability problems.
Convertible Top Mechanism:
Potential failures in the hydraulic pump, cylinders, and switches controlling the soft top operation.
Marque Legacy:
Mercedes-Benz is renowned for its engineering excellence, safety innovations, and luxury vehicles dating back to the late 19th century.
Predecessor:
Mercedes-Benz R107 SL-Class
Introduction Year:
1989 (as a 1990 model year vehicle)
Key Innovations R129:
Introduction of the M119 V8 engine, significantly updated aerodynamics, advanced safety features (rollover protection, ABS), and improved interior comfort.
Manufacturing Location:
Sindelfingen, West Germany (later Germany)
Production Span:
1989-2001 (R129 chassis)
Auto Magazine Ratings:
Consistently praised by automotive publications of its era for its build quality, performance, and luxurious appointments. Often featured in 'best of' lists for luxury convertibles.
Collector Status:
Highly regarded by collectors and enthusiasts for its timeless design and engineering, appreciating in value as a modern classic.
Safety Standards:
Compliant with all applicable European and North American safety standards for its production years.
