Alternator Replacement
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Alternator Replacement
Two days ago my alt locked up on my 1970 F-100(360, 3 on the tree, after market air{dealer installed?}. iwas about 20 min. from home and it was cold out so i cut the belt and drove on home, it never got hot.
The alt that i got from auto zone was suppose to be the right one-with air- because it had a double pully, although the old one was just a single. The connection post on the back are not placed the same but each are labled to match up.
Here is the problem the alt is putting out 14.8 v and the battery checked out ok on the auto zone tester, and it was showing 12.9 on the voltmeter at home, although atfer the truck was turned off the volts off the battery was dropping about .1 every second till it got down into the 11's. Every time I start it the battery sounds as if it is getting weaker, almost to the point that it is not going to turn it over.
Could i have hurt the battery driving home? It is only about a year old. Could the voltage regulator be bad?
Any help would be appreciated. If you need any more info let me know, I could really use some insight on this.
Ben Gibbs Rngr70(No Email Addresses In Posts!)
The alt that i got from auto zone was suppose to be the right one-with air- because it had a double pully, although the old one was just a single. The connection post on the back are not placed the same but each are labled to match up.
Here is the problem the alt is putting out 14.8 v and the battery checked out ok on the auto zone tester, and it was showing 12.9 on the voltmeter at home, although atfer the truck was turned off the volts off the battery was dropping about .1 every second till it got down into the 11's. Every time I start it the battery sounds as if it is getting weaker, almost to the point that it is not going to turn it over.
Could i have hurt the battery driving home? It is only about a year old. Could the voltage regulator be bad?
Any help would be appreciated. If you need any more info let me know, I could really use some insight on this.
Ben Gibbs Rngr70(No Email Addresses In Posts!)
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Joined: Jun 1999
Posts: 2,415
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From: Comox Valley, Canada
Alternator Replacement
Should not have hurt the battery on the drive home, actually should have been good for it to get a little more use than normal kind of like all of us "ole guys"
If the voltage is dropping below 12 volts after the truck is off there must be a current draw on the battery.
Try disconnecting the alternator wires and see if the voltage stops dropping, if it does the new alternator probably has a bad diode. If the voltage still drops with the alternator disconnected, then try disconnecting the voltage regulator. Same thing if that cures it replace the regulator.
If neither of these help. Disconnect the battery negative wire and put an ammeter between the battery negative post and battery negative wire. There should be very very minimal current draw, if any. If not start pulling fuses til the current indication on the meter drops. The fuse that causes the current draw to stop is the circuit that is the culprit.
Good luck.
Sparky
ps
See everyone in a few weeks I am off on a business trip
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