Alternator Issue (i think?)
 

i have been driving my 57 bird and noticed after couple drives the battery was drained. charged it for a couple days and started up right away. i think the car has the original alternator, and i wanted to know if there is a way to test to see if it is the alternator for sure, before i get a new one.
thanks.

Ford didn't switch from a generator to an alternator until 1965, so if you have an alternator, it's not original.

Attach a voltmeter to the battery. It should read just over 12 volts, typically 12.2 to 12.6. There are charts on the internet that relate this to state-of-charge, so download one and make that determination.

Then start the car and let it idle. The voltage should increase, typically in the range of 13.4 to 14.2. Generators typically don't make this voltage unless the engine is running at a higher RPM.

An alternator will have a separate regulator so that has to be checked too, but only if you're not getting the charging voltage.

Thanks @yadkin, i tried to test it with the volt meter, but i have been charging my car over night, so when i tested it before i started it, the battery was 13.3v. then i started it and at idle, the volt meter read 12.8v. so i took it to the mechanic down the street, he tested the alternator and said it was low. so im pretty sure i need a new alternator and/or voltage regulator? does any one know a place to get a rebuilt alternator. I saw that new alternators for this car are $375+. dont want to spend that much.
Thanks

You really need to make the determination if it is an alternator or generator. Here's a video explaining the difference. https://www.youtube.com/watch?v=4NsAYiUHsho

Important to note that after Ford went to an alternator in 1965, they still used an external regulator.

Also, I need to know your goal for the car- keep original, or to modernize.

okay thank you for that video, i wasnt sure before... but i currently have a generator in there, exactly like the one in that video, with an external regulator. i dont really have a preference as to keep it original or mordernize it, i am thinking of converting to an alternator only because it seems to be a little less expensive than getting a new generator. are there any down sides, what would you recommend @yadkin?

P.S. Thanks for the quick replies

For your car yes there is a huge downside for retrofitting an alternator, because an all original '57 is much more valuable then a resto-mod.

The good news is that both the original regulator and generator can be cleaned, checked and rebuilt. Start with the regulator. Inspect for loose wires and dirty or rusted contacts. Open up the cover and check for worn components. Buy a can of electric contact cleaner (Lowes or Home Depot) and use that to clean the interior parts.

Then test the regulator. It provides current to the generator to "excite" the electromagnets that in turn generate the electricity. Here's a video showing how that is tested. https://www.youtube.com/watch?time_c...ature=emb_logo

The generator is more rebuild-able. Refer to the earlier video- the brushes and contacts on the generator need periodic maintenance. The bearings wear out as well. I suggest that you do the job yourself because it is a simple job. If you can't do that then look for a local electric motor rebuild shop and take it and the regulator to them.

Here a rebuild kit is less than $50, and a rebuilt generator is under $180. I'm guessing that a local shop could do it for $100.

https://www.larrystbird.com/product-...nd-alternator/

Brand new regulator for less than $50.
https://www.rockauto.com/en/moreinfo...1338083&jsn=14

okay, thanks for the links they are very helpful. i am going to test all the wiring and if anything will try to rebuild the generator my self.

Ill let you know how it goes, probably wont be able to do it till later this month.

Rebuilding these little parts is the enjoyable part of this hobby. Once you take the generator apart, de-grease and clean the case, wire brush and sand off any rust, and repaint using Duplicolor engine paints. They make a Ford Black that is perfect.

yeah i have to start somewhere, thanks for the tip.

If you don't know the difference between an alternator and generator, you should not try to fix it. Talk to your so called mechanic and ask him where he get generators rebuilt. The rebuilder usually does regulators.

He knows now.

Rebuilding a generator is an easy job and a great place to start a long career as a DIYer in this great hobby. I used to own a '56 International Cub tractor and the rebuild kits for the starter (not much different than a generator) were about five bucks. Almost everything in 50's cars was made to be taken apart, cleaned and rebuilt.