Escort alternator bad?

I have a 94' Escort with the 1.9 engine. The alternator/battery charging light has been coming on, but only when the engine speed reaches about 2000/rpm. It goes out
when the RPM drops below 2K. The headlights dim a little when the warning light is on. They get brighter when the light goes out. This would seem to indicate that the alternator is not charging above 2K-RPM. I don't think the drive belt is slipping. There aren't any noises either. Suggestions?
Thanks
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The alternator brushes are worn out. Call NAPA and ask if they have a replacement set for that alternator.
That's if you dont have the money right now for a new or rebuilt.
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On Sat, 05 Nov 2005 03:28:45 GMT, Backyard Mechanic

I got brushes to fit my ford alternator from the local rebuilder for $4 or $5 the last time I replaced mine. IIRC about a half hour job after getting the alternator off.
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snipped-for-privacy@sny.der.on.ca wrote in

They're about 5 from NAPA as well..
Fordfan Go to Oct 18 post: Subject: TIP: Easy Alternator refurbish
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The slip rings can be slightly out of round.... if the brushes stick slightly in the holders, they can be able to follow the slip rings at low rpms but "float" at higher rpms.
Given the age of the car, I would probably opt for a good quality rebuilt... If finances are a concern, there is a chance of success in replacing the brushes and cleaning carefully. Having alternator ripple tested at low rpm may uncover failing diodes that may colour your decision. If you have a decent DMM, you can test for ripple using the AC 2 volt scale.... Start the engine and turn on all the accessories to load the charging system.... with the DMM on the AC 2 volt scale, attach one probe to a good chassis ground (not to the battery) and the other probe to the output terminal on the alternator. Ripple voltage should be below 0.5 volts.

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Likely needs new brushes - OK slow, but floating at speed.
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fordfan wrote:

I forgot to mention that the alternator is not the original. I had to replace that one about two years ago. I got a rebuilt one from 'Advance'. It's supposed to have a lifetime warranty so I'll take it back. Thanks for all the replies.
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