1991 Alternator

**David H.** · October 18, 2020, 05:31 PM

Re: 1991 Alternator

Originally posted by Craig Parkinson (67227)

I am new to Corvette ownership, and a new member of NCRS, so this is my first post to the Tech Discussion...
The alternator went out on my 1991 L98 Coupe. Can anyone share thoughts on where I can get a rebuild kit to restore the original alternator, and also comment on where I should buy up a new one?? I figure I can swap it out so I can continue to enjoy my occasional drives, then rebuild the original on my own time. The car is 100% original parts and low miles, and I would like to get it judged after COVID dies down, so keeping the original is important to me...
Thanks in advance for your response!!
~ Craig

Craig

Welcome to NCRS Tech Board! Link below may be of interest.

Take special care not to go with "blasting" or "tumbling" case clean-up. That will destroy your original finish and likely obliterate date and part number stampings.

Dave

https://www.forums.ncrs.org/showthread.php?119787-Home-brewed-alternator-restoration-possible&highlight=rebuild+alternator

**Joe L.** · October 18, 2020, 06:19 PM

Re: 1991 Alternator

Originally posted by Craig Parkinson (67227)

I am new to Corvette ownership, and a new member of NCRS, so this is my first post to the Tech Discussion...
The alternator went out on my 1991 L98 Coupe. Can anyone share thoughts on where I can get a rebuild kit to restore the original alternator, and also comment on where I should buy up a new one?? I figure I can swap it out so I can continue to enjoy my occasional drives, then rebuild the original on my own time. The car is 100% original parts and low miles, and I would like to get it judged after COVID dies down, so keeping the original is important to me...
Thanks in advance for your response!!
~ Craig

Craig-------

Your original alternator should be a GM #1101601 which is a 105 amp unit. I don't know of a kit, per se, that's available to rebuild your alternator. There may be some out there, though.

A high quality, rebuilt alternator is available for your application under GM #19152456 aka AC-Delco #321-388. Expect to pay about $150-175. You can use this to directly replace your alternator and it will be "plug-and-play". You could also obtain one of these to use as a parts source to rebuild your existing alternator. Basically, you would transfer the "guts" from the rebuilt alternator to your frame halves.

All of the GM parts to rebuild your alternator are discontinued but if you could find them, this is what you'd need:

GM #10474532---slip ring end bearing

GM #1989702----brush holder with brushes (also known as AC-Delco D775)

GM #1989703----capacitor

GM #10467052---rectifier bridge (+) (also known as AC-Delco D3990) this part may not be needed;test existing and re-use if good

GM #1116437----voltage regulator

GM #10474573---rotor (armature) probably will not be needed

GM #10494279---stator probably will not be needed

The following parts are currently available in the aftermarket:

brush holder with brushes---Standard Motor Products EX131

commutator end bearing----SKF 60002RSJ

drive end bearing-----National 203FF

You could also have your alternator professionally rebuilt. Among others, I believe that Ken Bruno Motorsports does this and advertises in the Driveline.

**Craig P.** · October 20, 2020, 03:41 PM

Re: 1991 Alternator

Thanks for the info, Joe!

After making a few clicks and calls, the local Chevy dealer pointed me to a local battery/electric business. They had three rebuilt AC-Delco #321-388 on the shelf for just $97 each, and they look brand new. Swapped out my original which I will have them rebuild. I made sure to tell them to NOT steel shot the case to insure the case numbers stay pristine... I can then swap it back in when I get the car judged, and have a spare in the garage to boot.

Thanks again,
Craig

1991 Alternator

1991 Alternator

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