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Anyone know what would cause an alternator to lose output as the engine gets warm? It only does it when the ambient temperature gets in the nineties or so.
 

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lol! I honestly cannot believe it still works....as I had lots of amperage being pumped from a stereo I had in it.....thought I would have fried it! It would get so hot though, it would make the belt smoke!
 

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Lose output .. how much? And are you going by dash Volt indicator or DVM?

That may be a feature not a bug.

Was working on wife's Bravada and noticed the output was 13.85 with car hot. I thought there was something wrong, I'd done a lot on Fords alts but never saw that much voltage reduction.
I googled and from chebby user forums found that was normal for a Delco VR. Fords, i'd seen drop from 14.6 to 14.2. Go figger.
Dropping out altogether is different thing, of course.
 

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Over time the brushes and contacts get worse; replacing those will usually bring it right back.

Replacing the regulator module, the bearings, and the brushes are much cheaper than an alternator, btw. :)
 

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Over time the brushes and contacts get worse; replacing those will usually bring it right back.
I said this poorly; you replace the brushes, but you Dress the rotor contacts. Gently. :) Same thing for starters.

I use fine sandpaper, and make the rotor surface as smooth as possible, while turning the rotor slowly.

Be sure no gouges, or sanding of wires! If you can't be careful, leave it alone, and just replace the brushes. :)


Anyone know:
Who sells chromed housings for these? Actually, what number or type are our alternators? 3G? 4G?
 

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I've been replacing starter and alternator brushes for years. I forgot to mention before but an indicator of worn brushes is that output stops at higher rpm's, typ. on the highway, and often starts again at lower to idle.
It's happened to me twice and the last time I got wise and rapped firmly on the back of the housing, same as you do a starter, which gave me enough time to get where I was going.

I've never sanded the rings, what I do is, clean them with a safe solvent. NOT carb cleaner or anything that reacts with paint so as to avoid softening varnish on the wires. I've used WD 40



Easy Alternator refurbish
 
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