🏷️ Basic Information

Make:

Mercedes-Benz

Model:

SL-Class

Model Code:

R129

Year:

1989

Chassis Code:

R129

👋 Introduction

Positioning:

The Mercedes-Benz SL-Class (R129) was positioned as a flagship luxury grand tourer and sports convertible, representing the pinnacle of Mercedes-Benz engineering and comfort for its era.

Competitors:

Competed with vehicles such as the Jaguar XJS, Porsche 911 Cabriolet, and Ferrari Mondial.

Design Highlights:

Iconic Pininfarina-influenced styling, advanced safety features for its time (e.g., integrated roll-bar), high-quality interior materials, sophisticated convertible top mechanism.

Target Audience:

Affluent individuals seeking a stylish, comfortable, and technologically advanced luxury convertible with renowned Mercedes-Benz build quality and reliability.

📋 Manual Details

Coverage Scope:

Comprehensive service and repair for all 1989 Mercedes-Benz SL-Class (R129) models.

Estimated Page Count:

800-1200 (typical for comprehensive factory service manuals of this era)

Type:

Factory Service Manual / Workshop Manual

Language:

English

Format:

Digital (PDF)

📖 Manual Coverage

Engine Mechanical:

Complete overhaul, diagnostics, timing, cooling, lubrication, fuel injection systems.

Engine Electrical:

Engine control unit (ECU), ignition system, sensors, actuators, wiring diagrams.

Transmission:

Automatic transmission (e.g., 4-speed 722.3/722.4, 5-speed 722.5 depending on specific engine variant), diagnostics, overhaul, fluid service, electronic control.

Drivetrain:

Driveshafts, differential, rear axle assembly.

Suspension:

Front and rear suspension components, struts, springs, control arms, bushings, power steering system.

Brakes:

Hydraulic system, ABS (Anti-lock Braking System), brake fluid specifications, pad/rotor replacement, caliper overhaul.

Steering:

Power steering system, steering gear, linkage, alignment specifications.

Electrical System:

Battery, charging system, starter, lighting, instrumentation, power accessories, convertible top hydraulics, wiring diagrams for all circuits.

Body And Interior:

Body panel repair, door mechanisms, convertible top operation and repair, interior trim, seats, HVAC system.

Climate Control:

Air conditioning system operation, refrigerant, components, diagnostics.

Diagnostics:

Troubleshooting guides, fault codes, diagnostic procedures.

Maintenance:

Routine service, oil changes, filter replacements, fluid checks and top-offs, scheduled maintenance intervals.

Repair:

Component removal, installation, overhaul, and replacement for all major systems.

Troubleshooting:

Step-by-step diagnostic procedures for identifying and resolving common and uncommon problems.

Specifications:

Torque specifications, clearances, fluid capacities, wear limits, alignment data.

Wiring Diagrams:

Detailed electrical schematics for all vehicle systems.

Depth:

From basic maintenance to complete engine and transmission rebuilds, including complex electronic system diagnostics.

📊 Manual Specifications

Quality:

High-resolution, searchable PDF with clear text and legible diagrams.

Print Compatibility:

Optimized for printing individual sections or the entire manual.

Binding Recommendation:

For printed copies: Spiral or comb binding for lay-flat usability.

Paper Recommendation:

For printed copies: Matte or semi-gloss finish paper for clear diagram reproduction.

⚙️ Engine Specifications

Engine Variant 1:

300 SL-24 (M104.980) - 3.0L DOHC Inline-6

Engine Variant 2:

500 SL (M119.960) - 5.0L DOHC V8

300 Sl-24 Horsepower:

228 hp @ 6,000 rpm

300 Sl-24 Torque:

205 lb-ft @ 4,500 rpm

500 Sl Horsepower:

322 hp @ 5,500 rpm

500 Sl Torque:

354 lb-ft @ 3,750 rpm

Fuel Injection Type:

Bosch KE-Jetronic (500 SL), Bosch HFM (some later 300 SL-24 variants, though 1989 primarily KE-Jetronic)

Fuel Type:

Premium Unleaded Gasoline

Engine Block Material:

Aluminum-silicon alloy (M119 V8), Cast iron (M104 Inline-6)

Cylinder Head Material:

Aluminum

Coolant Type:

Mercedes-Benz approved coolant (e.g., G48 or equivalent) mixed 50/50 with distilled water.

🔧 Transmission

Standard Transmission:

4-speed automatic transmission (e.g., 722.3 for M119, 722.4 for M104)

Optional Transmission:

5-speed automatic transmission (722.5) became available on some models later in the R129's lifecycle, but less common for 1989.

Transmission Control:

Electronic control for shift points and operation, often with sport/economy modes.

Automatic Transmission Fluid Type:

Dexron II (or equivalent MB specification)

Automatic Transmission Fluid Capacity:

Approximately 8.0 - 9.0 liters (varies by model and torque converter drain plug availability).

📐 Dimensions

Length:

Approx. 4,450 mm (175.2 in)

Width:

Approx. 1,810 mm (71.3 in)

Height:

Approx. 1,290 mm (50.8 in)

Wheelbase:

Approx. 2,515 mm (99.0 in)

Curb Weight 300Sl:

Approx. 1,720 kg (3,790 lbs)

Curb Weight 500Sl:

Approx. 1,850 kg (4,080 lbs)

Gross Vehicle Weight Rating:

Not explicitly stated for 1989 consumer models, typically around 2100-2200 kg.

🛡️ Safety Features

NHTSA Ratings:

Specific NHTSA ratings for the 1989 R129 are not readily available in a standardized format comparable to modern vehicles. However, Mercedes-Benz vehicles of this era were known for robust construction and advanced safety engineering.

ABS:

Standard Anti-lock Braking System (ABS) on all models.

Traction Control:

Optional ASR (Acceleration Slip Regulation) available on some models/markets.

Airbags:

Driver's side airbag was standard.

Roll Bar:

Automatic, hydraulically operated roll-bar that deploys in milliseconds in the event of a rollover.

Seat Belts:

Force-limiting front seat belts with pre-tensioners.

Body Structure:

Reinforced A-pillars and body structure for enhanced occupant protection, particularly in convertible configuration.

💡 Technology Features

Audio System:

Premium sound systems, often with cassette players and AM/FM radio. CD changers were optional.

Climate Control Interface:

Automatic climate control with digital displays and manual overrides.

Cruise Control:

Standard electronic cruise control.

Pre Wired For Phone:

Optional cellular telephone integration was available in some markets.

Power Seats:

Standard power-adjustable front seats with memory functions.

Power Windows Locks:

Standard power windows and central locking system.

🔧 Maintenance

Oil Change Interval:

Typically every 7,500 - 10,000 miles or 12 months, whichever comes first, depending on driving conditions (refer to manual for specific recommendations).

Major Service Interval:

Major services (e.g., spark plugs, coolant flush, transmission service) usually at 30,000, 60,000, and 100,000 miles.

Engine Oil Type:

API SG/SH rated synthetic or semi-synthetic oil, viscosity typically 0W-40 or 5W-40 for European climates, or 15W-40 for hotter regions (refer to manual for exact MB specification).

Engine Oil Capacity:

Approx. 8.0 liters (M104), 8.5 liters (M119) with filter change.

Power Steering Fluid:

MB specification hydraulic fluid (e.g., Febi Bilstein CHF 11S or equivalent).

Brake Fluid Type:

DOT 3 or DOT 4 brake fluid.

Wiring Harness:

Degradation of insulation on early model wiring harnesses (specifically around the engine bay) can lead to electrical faults.

Convertible Top Hydraulics:

Leaks or failures in the hydraulic system for the power convertible top mechanism are common with age; seal degradation is a frequent culprit.

Mass Air Flow Sensor:

MAFS can become contaminated or fail, affecting engine performance and fuel economy.

Window Regulators:

Electric window regulators can fail due to wear and tear on the motor or mechanism.

ABS Sensors And Module:

ABS wheel speed sensors can fail, leading to ABS warning lights and system malfunction.

Biodegradable Wiring Insulation:

Some engine wiring harnesses from this era use insulation that can degrade over time, causing shorts and driveability issues.

📚 Vehicle History

Heritage Association:

The SL-Class has a long and prestigious lineage dating back to the iconic 300 SL 'Gullwing' of the 1950s, representing Mercedes-Benz's commitment to luxury, performance, and innovation in open-top motoring.

R107 Replacement:

The R129 generation succeeded the R107 SL-Class, introducing a completely new chassis, advanced technology, and significantly enhanced safety features.

Production Period:

The R129 platform was produced from 1989 to 2001.

Manufacturing Location:

Bremen, Germany

🏆 Awards & Recognition

Automotive Press:

Consistently praised by automotive journalists for its blend of performance, luxury, and groundbreaking safety features. While specific 'awards' are less common for model years compared to new launches, its design and engineering were highly acclaimed.

Resale Value:

Well-maintained examples typically hold strong resale value due to their enduring desirability and Mercedes-Benz reputation.