Broken alternator brush?

Vehicle: 2005 buick lacrosse cx 3.8L
Recently had p0621 code, generator l terminal circuit
malfunction. Tested battery and alternator with multimeter, getting no charge (below 12.4v). Take alternator off and into shop for bench test, not generating, but diodes passed. Got home and took it apart to check brushes, and low and behold one of the brushes was not connected anymore, the wire on the back of it was frayed and broken. After much searching, I found a rebuild kit (couldnt find just the Volt regulator and brushes) and am waiting on it to arrive. My question is what could have caused the fray/break? I dont want to replace the regulator only to have another brush break. Any help or input would be appreciated

That’s probably due to bad handling during assembly of the brush holder.
This could be fixed with some soldering skills, at least to tide over until a new part comes.

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Just get a rebuilt alternator.

Unfortunately I dont know how to solder , I probably should learn hah. Also, I dont know if it would reach, the broken end was pretty far back in regulator. Looked for a way to get just brushes out but the only guides I could find involved drilling them out and resoldering. Part should be here in a week, come on post office!

I checked for one, it was $43 for rebuild kit or $180+tax for rebuilt alt. If I had plenty of money I probably wouldnt bother, but saving $150 right now is kind of necessary. Also looked into grabbing a junkyard one for $50, but couldnt find one local that i could pull myself and i dont trust salvage part pullers to send me a good one

Was that $180 before or after the old alternator is sent in? I paid a core charge at my local parts store for alternators in the past, which is credited to my credit card when I return with the old alternator for rebuild. I think the cost with core charge was around $180, much less with returned dead unit.

No and got basically the same price everywhere I checked. All around $180 base, then $50-$60 additional core charge. Feelsbad

The core charge for one of my Toyota’s alternator was a whole ten dollars!. Like an idiot, I returned the old alternator and got my ten bucks back. I should have kept it , sent it out for new bearings and brushes, and kept it as a spare.

This was back in 1998. I guess core charges went up

Look for a nearby shop that installs car audio or alarms.
Find a friendly tech and he/she might do it no charge.
Re. reach: a little stranded wire can bridge the gap.
If it weren’t for COVID I’d suggest dropping by the Electrical Engineering dept of a college campus, or a tech school.


Thanks, I didn’t even think of that. I’ll give it a shot, have a week until new regulator supposed to arrive anyway.

Going through all these gyrations while leaving the current bearings in there (with who knows how many miles) is, in my opinion, foolish.

Why did it break? 15 years and xxxx miles worth of vibrations.

Dont try to repair that braided copper going to the brush… It is so contaminated with powdered graphite that you will never get the solder to stick…anywhere. Its just too dirty and its not going to buy you much to patch it. Especially with the new component on the way.

All you need to do now is wait.

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I think probably NAPA has one in stock or can get it in a day. These used to be about $10 when I would regularly overhaul my alternators about every 70K. I have not had good luck with rebuilt alternators unless they were Delco and I would not solder the brush wire since these need to be flexible as the brush continually moves.

The bearings are fine, but the as I said I had to buy a full rebuild kit so I’m getting new bearings if they start to go. The alternator is right on top of these, very easy to get on and off.

Dang maybe I should’ve tried them again haha. I called every local auto/parts store near me and no one would even order one. Called napa about 10 minutes before their closing time, someone picked up the phone and hung up right away. Called back and no answer so I didn’t try them again.

You need to go to one of those small auto electric shops . . . the kind where the guy actually rebuilds starters, alternators, etc.

They’ll be able to solder on new brushes . . . and it’ll probably cost you little

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Like I said, when I would rebuild my own I would replace the brushes, voltage regulator, diode trio, the front bearing and every two rebuilds or so also the rear bearing. I never had one fail on me but these are the parts that fail. Usually everything was somewhere around $25 with the voltage regulator the highest cost. Hardly anything for the other parts. Last one I tried though the field windings were crimped or something instead of bolted so you couldn’t get it apart-reasonably. But gee, if you got it all apart, just change the stuff that fails and clean it up.

Make me miss my 61 dodge dart. New brushes were 25 cents and it took a minute to change them with a Phillips screwdriver right in place.

Were they welded . . . ?