When replacing the alternator, you don't adjust the tension. The process involves:
1. Loosening the alternator mounting bolts: This will allow the alternator to move slightly.
2. Removing the belt: Usually, you can work the belt off the alternator pulley and the other pulleys without needing to significantly loosen the tension. Sometimes slightly prying the idler pulley *might* help, but forceful action isn't necessary on this system. If the belt is particularly stubborn, you might need a belt tensioner tool.
3. Replacing the alternator: Carefully remove and install the new alternator, making sure it's properly aligned with the mounting bolts.
4. Installing the belt: Route the belt correctly over all the pulleys, ensuring it's seated properly in each groove. The spring-loaded idler pulley will automatically adjust the belt tension.
If the belt is still too loose or too tight after installing the new alternator:
* Too loose: This is uncommon with these self-adjusting systems and might indicate a problem with the idler pulley itself, or a worn belt. Replace the belt with one of the correct length for your Beretta's engine. A worn idler pulley would also need replacing.
* Too tight: This is also unlikely, but could be caused by the idler pulley sticking. Try moving the idler pulley by hand to make sure it moves freely. Again, a replacement might be necessary.
Important Note: Always consult a repair manual specific to your 1989 Chevy Beretta's engine (e.g., a Haynes or Chilton manual) for detailed instructions, diagrams, and torque specifications. Incorrect installation can lead to premature belt wear, alternator damage, or even engine damage.
