76 Regency

Hey gang,

I'm trying to figure out what's up with my alternator. The one in my black 98 is a Delco rebuild and hardly has any miles on it as I've only just started driving the car in the last few months. JUST before going to its first show, I noticed that the "GEN" light was dimly lit. With limited time before the show, I swapped alternators with my red 98 and it's been perfect since. I replaced the voltage regulator, cleaned the armature and the light is still on. Mind you this alternator is now in a different car so it's not the car. The brushes are in pretty good shape (still enough that the hole to hold them in place is well intact. Should I try a new set of brushes as well and/or anything else? What other serviceable parts can I replace on it...the rectifier???

I've been driving the car around a bit like this and it's running and seems to be charging ok. It started up just fine after 2-3 weeks of sitting in the cold (Northeast).

Any ideas ?

Thanks!

Rickman48

Sounds like a diode went out - might go to your local rebuilder, explain, and let them fix it!

stellar

It sounds like a bad diode trio. You may as well replace the rectifier and trio.

rustyroger

I agree with Rickman and Stellar, a dim gen light is a classic symptom of a diode gone bad, you might as well have it completely overhauled and forget about charging woes for a long while.

Roger.

76 Regency

Thanks for the quick replies guys. It's bothering me that this is a Delco rebuild and it's having problems. I put in a brand new voltage regulator and it's the same. I'd hate to pay to have it rebuilt again and possibly end up in the same situation.

What's your experience with Delco rebuilt parts vs local shops, etc?

Appreciate the help guys.

Rickman48

Most rebuilders just check to see if they're [diodes] good or bad - there's no way to determine when they'll go out!
That's why I recommended the local rebuilder vs paying for another rebuilt, [unless under warrantee] as they should be able to just replace the diode trio.
If I brought the alternator in, they'd do it while I waited, and charge $20 - 35 yrs. ago!

76 Regency

OK, thanks for the info Rick. I need to find a local rebuilder and see what they can do for me. Hopefully it's a quick, simple fix. Maybe I'll come out of this with a great new local shop I can rely on in the future. Thanks again!
John

stellar

I have been rebuilding alternators starters and generators for 37 years. I have seen some good and some bad Delco remans. They did a very bad job of rebuilding the CS130 alts. An independant rebuilder has much better Cs130 than Delco. You can probably repair yours yourself if it is the stock alt type 12SI. If you already put a regulator in it you can do the diodes too. You can probably buy the parts at a local parts store. If not I can send them to you. If you want I can try to locate a local rebuilder for you. We rebuilders have a forum of our own and help each other out. I can ask if someone is near you and get back to you. Let me know what city you are in. Mark.

Lady72nRob71

John, if yours is a 12si and you are thinking about replacing the diodes yourself, here is a thread that might help you.
https://classicoldsmobile.com/forums...lternator.html
PArts are available for cheap at the local parts store and it is a pretty easy job...

Mark, glad to have you around providing advice and services to CO members!

76 Regency

Wow, thanks Mark! I should have known there was a forum like you mentioned..it seems there's one for just about everything now which is so great! I'm in Danbury, CT. Let me know who you know of around here and thanks again!!

Hey Rob,

thanks for the link. I will definitely check that out. By the way, did you see the post I submitted about a week ago for a '72 Cutlass convertible that's for sale near me? It reminded me of Lady when I first saw. Check it out if you haven't already. It's a fairly nice car that needs some TLC and the right home.

https://classicoldsmobile.com/forums...ats-worth.html

stellar

call Joe at all tech 203-790-8990 Open till 5 saturday too. I don't know him , but check it out and see what happens. Good luck let me know what happens. Mark

76 Regency

hey Mark, thank you for the info. I will definitely call Joe and let you know what comes of it. Thanks for all the help!
John