1. Disconnect the battery.
* This is important to prevent any electrical shocks while you are working. Disconnect the negative terminal first, and then the positive terminal.
2. Remove the serpentine belt.
* The serpentine belt is the long, thin belt that runs around the front of the engine. To remove it, you will need to loosen the tensioner pulley. The tensioner pulley is located on the passenger side of the engine, near the top. Once you have loosened the tensioner pulley, you can slip the serpentine belt off of the pulleys.
3. Remove the alternator.
* The alternator is located on the passenger side of the engine, near the bottom. It is held in place by three bolts. Remove the bolts, and then lift the alternator out of the engine compartment.
4. Install the new alternator.
* Place the new alternator into position in the engine compartment. Replace the bolts that you removed in step 3. Tighten the bolts until they are snug.
5. Reinstall the serpentine belt.
* Slip the serpentine belt back onto the pulleys. Tighten the tensioner pulley until the belt is tight.
6. Reconnect the battery.
* Reconnect the positive terminal first, and then the negative terminal.
7. Start the engine and test the alternator.
* Start the engine and let it run for a few minutes. The alternator should charge the battery. You can check the battery voltage with a voltmeter. The battery voltage should be around 14 volts.
8. Turn off the engine and reconnect the battery.
* Turn off the engine and reconnect the battery. You are now finished changing the alternator on your 1998 Ford Expedition.
