Alternator going bad.
Thread Starter
Melting Slicks
Joined: Aug 2010
Posts: 2,487
Likes: 10
From: Palm Beach Florida
St. Jude Donor '12
Alternator going bad.
My alternator is showing signs of it going. When at idle she reads 13 V. But the generator light comes on and off. When I step on the accelerator she immediatly goes right up to 18 V. So I know it's time. Is there a preference to what kind I should get? Thinking that maybe I want one with a chrome case to dress up the motor a bit. What do you think? (77-L48 Auto)
Race Director
Joined: Nov 2002
Posts: 12,142
Likes: 54
From: Taylor Michigan
reading 18 volts will blow out electrical parts that only need 12 volts like bulbs ect...that are probably brighter than hell...you need that corrected and its a good chance its the regulator....and most Corvettes use a alternator with a built in regulator depending on the year
Thread Starter
Melting Slicks
Joined: Aug 2010
Posts: 2,487
Likes: 10
From: Palm Beach Florida
St. Jude Donor '12
My alt. has a plug with two wire on the top side. and one wire that bolts to the back. Does this make it a 3-wire hook up (is the plug called a pigtail?) Or do I have what they call a One wire alternator? Looking at a lester 7127-105c. Not sure if it will fit. I believe it will.
Safety Car
Joined: Jun 2004
Posts: 4,374
Likes: 224
From: Beecher Illinois
Or rebuild it yourself. They're not really a big mystery.
If it's original to the Vette and dated/numbered correct, at least don't trade it in.
Rebuilding is simply replacing the stuff in the back of the alternator and the bearings. And clean the case up, I use "Barkeepers Friend" and water and some stiff brushes.
If you decide to go this route I or many others here can talk you through it.
If it's original to the Vette and dated/numbered correct, at least don't trade it in.
Rebuilding is simply replacing the stuff in the back of the alternator and the bearings. And clean the case up, I use "Barkeepers Friend" and water and some stiff brushes.
If you decide to go this route I or many others here can talk you through it.
Last edited by KapsSA; Feb 2, 2011 at 01:46 AM.
Race Director
Joined: Mar 2006
Posts: 14,112
Likes: 28
From: Florida
The regulator is bad. Max on yours should be no more than 14.7v and 55˜amps.
You have a standard regulator in yours, not a 1 wire.
If yours is the original, then just get a cheapie replacement and keep yours to rebuild at your leisure, parts are cheap, only a few minutes to change out.
Here's a 63 amp for yours that you can get locally.
http://shop.advanceautoparts.com/web...S_539074357___
You have a standard regulator in yours, not a 1 wire.
If yours is the original, then just get a cheapie replacement and keep yours to rebuild at your leisure, parts are cheap, only a few minutes to change out.
Here's a 63 amp for yours that you can get locally.
http://shop.advanceautoparts.com/web...S_539074357___
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Thread Starter
Melting Slicks
Joined: Aug 2010
Posts: 2,487
Likes: 10
From: Palm Beach Florida
St. Jude Donor '12
Im gonna check it out today.(see if it is an original) That is why I was asking about this Alt. lester (7127-105c.) It is cheap and will would be great to put in its place while I do a rebuild and clean the original. Thanks for all the help
Thread Starter
Melting Slicks
Joined: Aug 2010
Posts: 2,487
Likes: 10
From: Palm Beach Florida
St. Jude Donor '12
The regulator is bad. Max on yours should be no more than 14.7v and 55˜amps.
You have a standard regulator in yours, not a 1 wire.
If yours is the original, then just get a cheapie replacement and keep yours to rebuild at your leisure, parts are cheap, only a few minutes to change out.
Here's a 63 amp for yours that you can get locally.
http://shop.advanceautoparts.com/web...S_539074357___
You have a standard regulator in yours, not a 1 wire.
If yours is the original, then just get a cheapie replacement and keep yours to rebuild at your leisure, parts are cheap, only a few minutes to change out.
Here's a 63 amp for yours that you can get locally.
http://shop.advanceautoparts.com/web...S_539074357___
Safety Car
Joined: Jun 2004
Posts: 4,374
Likes: 224
From: Beecher Illinois
This is a 79 alternator....
The 79D12 is the date, April 12, 79. Your date should be up to a few months to a couple weeks before your Vette's production date. It might not be '77', just '7'.
Part no above it.
I believe possible part nos. for 77 are....
1102474
1102484
1102908
1102909
The 79D12 is the date, April 12, 79. Your date should be up to a few months to a couple weeks before your Vette's production date. It might not be '77', just '7'.
Part no above it.
I believe possible part nos. for 77 are....
1102474
1102484
1102908
1102909
Last edited by KapsSA; Feb 2, 2011 at 12:56 PM.
Race Director
Joined: Nov 2002
Posts: 12,142
Likes: 54
From: Taylor Michigan
I would not be looking to expect the original alternator to still be on a 35 or so year old car....But the numbers are stamped into the rear case
Not even close.
