This comprehensive service and repair manual is specifically designed for the BMW 5-series (E12) model year 1978. It offers detailed instructions, diagrams, and illustrations to guide you through every aspect of maintaining, servicing, diagnosing, and repairing your vehicle. This is the same manual used by technicians at BMW dealerships, ensuring you have access to the most accurate and up-to-date information.

The manual covers a wide range of topics, including:

* **Maintenance:** Routine maintenance procedures and schedules, ensuring your vehicle runs smoothly and efficiently.
* **Engine:** Detailed information on engine components, operation, troubleshooting, and repair.
* **Control System:** Comprehensive coverage of engine control systems, including electronic components, sensors, and diagnostics.
* **Mechanical:** In-depth explanations of mechanical systems such as the transmission, drivetrain, axles, suspension, and steering.
* **Fuel Service Specifications:** Provides specifications and procedures for maintaining and repairing the fuel system, including injectors, pumps, and lines.
* **Emission Control:** Covers the emission control system, including catalytic converters, oxygen sensors, and related components.
* **Intake Exhaust Cooling:** Detailed information on the intake and exhaust systems, including cooling components.
* **Lube:** Specifications and procedures for proper lubrication of engine, transmission, and other components.
* **Ignition Starting Charging:** Covers the ignition system, starting system, and charging system.
* **Auto Transmission Clutch:** Provides comprehensive information on automatic transmission operation, maintenance, and repair.
* **Manual Transmission:** Detailed explanation of manual transmission operation, repair, and maintenance.
* **Transfer Propeller Shaft:** Covers the transfer case, propeller shaft, and related components.
* **Drive Shaft:** Detailed information on drive shafts, including maintenance and repair.
* **Differential:** Comprehensive coverage of the differential, including operation, diagnosis, and repair.
* **Axle Suspension:** Step-by-step instructions for maintaining and repairing the axle and suspension system.
* **Tire & Wheel:** Information on tires, wheels, and related components.
* **Brake Control:** Covers the brake control system, including hydraulics, sensors, and electronics.
* **Brake:** Detailed information on brake components, operation, maintenance, and repair.
* **Parking Brake:** Detailed information on the parking brake system, including operation, diagnosis, and repair.
* **Steering Column:** Covers the steering column and related components.
* **Power Steering:** Provides information on power steering operation, maintenance, and repair.
* **Air Condition:** Detailed information on the air conditioning system, including operation, diagnosis, and repair.
* **Suppl Restraint System:** Covers the supplemental restraint system, including airbags and seatbelt pretensioners.
* **Seat Belt:** Information on seatbelts, including operation, maintenance, and repair.
* **Engine Immobilizer:** Explains the engine immobilizer system and how it works.
* **Cruise Control:** Covers the cruise control system, including operation, diagnosis, and repair.
* **Wiper & Washer:** Provides information on windshield wipers and washers, including operation, maintenance, and repair.
* **Door Lock:** Covers door locks and related mechanisms.
* **Meter Audio/Visual:** Information on the instrument cluster and audio/visual components.
* **Horn:** Details on the horn system and related components.
* **Windshield/Glass Mirror:** Covers windshield, glass, and mirrors, including replacement and repair.
* **Instrument Panel:** Information on the instrument panel and related components.
* **Seat:** Detailed instructions for seat maintenance and repair.
* **Engine Hood/Door:** Covers the engine hood and doors, including maintenance and repair.
* **Exterior & Interior:** Provides information on exterior and interior components, including trim, body panels, and upholstery.
* **Electrical:** Comprehensive coverage of electrical systems, including wiring diagrams, components, and troubleshooting.
* **Multiplex/Can Communication:** Explains the multiplex and CAN communication systems.

This manual provides you with the knowledge and guidance to handle most service and repair tasks on your BMW 5-series (E12) confidently. This can save you significant time and money by reducing your reliance on professional mechanics and enabling you to perform repairs yourself.

The BMW 5-Series (E12) is a car that holds a special place in automotive history, marking the beginning of the iconic 5-Series line. Introduced in 1972, the E12 represented a significant departure from its predecessor, the BMW 1800/2000, by offering a more spacious and luxurious interior, improved handling characteristics, and a wider range of engine options. The E12's design, penned by Paul Bracq, was a stark departure from the more rounded lines of the earlier BMWs, featuring a sharp, angular profile that was both elegant and sporty.

The E12 5-Series was truly groundbreaking for its time, offering a blend of performance, luxury, and practicality that appealed to a wider audience than ever before. Its rigid chassis and independent suspension provided exceptional handling and stability, while its powerful engine options, ranging from the 2.0-liter four-cylinder to the 3.5-liter six-cylinder, offered exhilarating performance. The E12 also introduced several technological innovations, including the first use of anti-lock brakes (ABS) on a production BMW. The E12 helped establish the BMW 5-Series as a benchmark for mid-size executive sedans, setting the stage for the future success of the nameplate.