Tools You'll Likely Need:
* Socket wrench set (metric)
* Ratchet
* Extensions
* Wrenches (metric)
* Possibly a breaker bar for stubborn bolts
* Screwdrivers (Phillips and flathead)
* Wire brush (to clean battery terminals and alternator connections)
* New alternator (ensure you get the correct one for your vehicle)
* Jack and jack stands (highly recommended for safety)
* Safety glasses
* Gloves
Steps:
1. Disconnect the Battery: Disconnect the negative (-) battery cable first, then the positive (+) cable. Keep the cables separate to prevent accidental shorting.
2. Access the Alternator: The alternator is typically located on the front of the engine, near the driver's side. You'll need to access it by possibly removing:
* Serpentine Belt: This is usually the biggest hurdle. Use a belt tensioner tool (or if your tensioner is manually adjustable, a wrench) to release the tension on the belt, allowing you to remove it from the alternator pulley and other pulleys. There are numerous videos online demonstrating how to do this for a 1990 Ford Ranger 2.9L – search for "1990 Ford Ranger 2.9L serpentine belt removal."
* Other Components: Depending on your Ranger's configuration, you might need to loosen or remove other components (like hoses or brackets) to get a clear shot at the alternator.
3. Disconnect Electrical Connections: Carefully disconnect the wiring harness connectors from the alternator. Take pictures or make notes before disconnecting to ensure you reconnect them correctly. Often, there's a large bolt connection for the main power wire and smaller connectors for the alternator's indicator light.
4. Remove the Alternator Mounting Bolts: Usually, there are two or three bolts holding the alternator to the engine block or bracket. Remove these bolts.
5. Remove the Alternator: Carefully remove the alternator from its mounting location. It might be slightly heavy.
6. Install the New Alternator: Install the new alternator in the reverse order of removal. Ensure all mounting bolts are tightened to the manufacturer's specified torque (check your repair manual).
7. Reconnect Electrical Connections: Reconnect the electrical connectors to the new alternator, making sure they are securely fastened.
8. Reinstall the Serpentine Belt: Reinstall the serpentine belt, ensuring it's properly seated on all the pulleys.
9. Reconnect the Battery: Reconnect the positive (+) battery cable and then the negative (-) cable.
10. Start the Engine: Start the engine and check for any warning lights. Verify the alternator is charging the battery by checking the voltage at the battery terminals with a voltmeter (should be around 13.5-14.5 volts when the engine is running).
Important Considerations:
* Repair Manual: A factory service manual or a reputable aftermarket repair manual for your specific 1990 Ford Ranger 2.9L is highly recommended. It will provide detailed diagrams, torque specifications, and other crucial information.
* Safety: Always prioritize safety. Use jack stands when working under the vehicle. Wear safety glasses and gloves.
* Belt Routing: Make absolutely certain you route the serpentine belt correctly. Incorrect routing can damage the belt and other components.
* Professional Help: If you're not comfortable performing this repair yourself, consider taking your vehicle to a qualified mechanic.
This guide is for informational purposes only. Improper repair can damage your vehicle. Consult a repair manual and proceed with caution.
