When a hobbyist opens the hood of his or her vintage vehicle, the alternator generally isn’t what’s admired most. In fact, short of a charging system issue that forces action, the belt-driven voltage generator is so reliable that it can operate inconspicuously for years without maintenance. Nothing underhood is truly maintenance-free, however, and our Pontiac’s alternator proved just that. It wasn’t a charging issue that drew our attention. Instead, a persistent chatter at idle speed indicated something was amiss. A cursory check revealed that an internal bearing was beginning to fail, and without swift action it could leave us stranded.
Our ’76 Firebird was originally equipped with a 10SI (or System Integrated)-series alternator developed and produced by GM’s Delco-Remy division in a variety of sizes and output ratings. While remanufactured 10SI alternators are typically stocked at local parts stores, we find originality important and decided to completely disassemble our Firebird’s original 80-amp unit and replace its shaft bushings. That then afforded us the opportunity to replace the internal electronics, essentially resulting in a complete alternator rebuild. Follow along to see how we did it.