Tools You'll Need:
* Socket set (metric): Various sizes, including likely 10mm, 13mm, 15mm, and possibly larger.
* Wrench set (metric): For those hard-to-reach bolts.
* Ratchet and extensions: To reach those hard-to-reach bolts.
* Pliers: For disconnecting electrical connectors.
* Screwdrivers: Phillips and flathead.
* Jack and jack stands: Essential for safety. Never work under a car supported only by a jack.
* Wheel chocks: To further secure the vehicle.
* New alternator: Make sure you get the correct replacement for your specific model.
* Battery terminal cleaner: Recommended.
* Gloves and safety glasses: Always protect yourself.
* Torque wrench: Highly recommended for proper tightening of bolts.
* Possibly a pulley puller: Depending on how the alternator pulley is attached.
* Shop rags: For cleaning up spills and keeping things tidy.
Steps (General Outline):
1. Disconnect the battery: Disconnect the negative (-) terminal first, then the positive (+). This prevents accidental shorts and injury.
2. Access the Alternator: The alternator's location varies slightly depending on the engine, but it's usually located on the front of the engine, often near the bottom. You'll likely need to remove some components for better access. This might include:
* Air intake system: Potentially needs to be partially or fully removed.
* Belt tensioner: You'll likely need to loosen the belt tensioner to remove the serpentine belt. This often involves a special tool or carefully using a wrench.
* Other components: Consult your repair manual for specifics.
3. Remove the Serpentine Belt: Route the belt off the alternator pulley, then the other pulleys, after loosening the tensioner.
4. Disconnect Electrical Connectors: Disconnect the electrical connectors from the back of the alternator. Take photos or make notes so you can reconnect them correctly later.
5. Remove the Alternator Mounting Bolts: There are usually two or three bolts securing the alternator to the engine. Remove these bolts.
6. Remove the Alternator: Carefully remove the alternator from its mounting location. It may be a little snug.
7. Install the New Alternator: Install the new alternator, reversing the removal process. Make sure all the bolts are tightened to the manufacturer's specifications (use a torque wrench).
8. Reconnect Electrical Connectors: Connect the electrical connectors securely.
9. Install the Serpentine Belt: Route the serpentine belt back onto all the pulleys, ensuring it's properly seated on each pulley. Tighten the belt tensioner.
10. Reconnect the Battery: Connect the positive (+) terminal first, then the negative (-) terminal.
11. Start the Engine: Start the engine and check for any warning lights on the dashboard. Also, check the belt tension.
12. Test the Alternator: Use a multimeter to verify the alternator is charging the battery correctly. A good charging voltage will be around 13.5-14.5 volts when the engine is running.
Important Notes:
* Safety First: Always prioritize safety. Disconnect the battery, use jack stands, and wear appropriate safety gear.
* Repair Manual: A repair manual specific to your 1995 Cadillac STS is invaluable. It will provide detailed diagrams, torque specifications, and step-by-step instructions.
* Professional Help: If you're not comfortable performing this repair yourself, take your car to a qualified mechanic.
This is a complex repair. Improperly installing the alternator can lead to further damage. If you are unsure about any step, seeking professional help is strongly recommended.
