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Changing brushes in Alternator

Shouldn't be a huge problem - is your alternator ND (should be for 1991 and up) or Delco (1984-1990, gasoline engine?)

I don't recall what the Renault Diesel used, and I have no idea what the VAM Diesel used, either...

The most "job-specific" tool you should really need is a toothpick.

5-90
 
100 thousand miles is probably a little young to worry about, but no harm in doing it anyway if you're just itching for a project. I'd wait until the thing misbehaves, which might never happen anyway. I've had alternators go over 250K miles without service. If you do replace the brushes do not be tempted to sand the slip rings to clean them, even with ultra-fine paper, unless they're already galled or damaged. The surface is very very smooth, and not meant to be cleaned with anything stronger than crocus cloth. It's better if you can just leave them alone or clean them gently without abrasion. Even a little roughness will shorten brush life significantly.
 
The main failure of an alternator is with the bearings. They get sloppy and allow the stator and rotor to "kiss". That spells death. So, if you change anything, put in new bearings. As a preventive maintenace procedure, I think 100K miles is probably a good time for new bearings. My experience with bearing failure has been arround 125K or so.
 
How hard is it to determine bearing pn's and brush pn's prior to tear-down?!?
 
mikeny59 said:
How hard is it to determine bearing pn's and brush pn's prior to tear-down?!?
Click to expand...

I'm working on that - I've got a Borg-Warner catalogue that I've been plugging into my master Excel sheet, so I can organise things before I code them into HTML...

Catch is, pages like that are probably still a couple of months out. I typically work on stuff like that "when I have time" - which means I'm on a train, sitting in an ER with my mother-in-law, or otherwise at loose ends with nothing else I can do (my laptop goes pretty much where I go, and I've got an inverter and a power supply in each truck anyhow...)

5-90
 
I contacted a local motor/alternator re builder who was happy to tell&sell me the parts I needed; just gave him the model number of my alternator. At the time, he advised me that my particular alternator--the one originally installed on a 4.0l, Laredo model, had inherently bad bearings, and advised I install an upgrade--which I did.
 
good news...
 
I started getting an intermittent check engine light (code 41) in my 94 at 220k miles. I opened up the alternator and the brushes are down to their last nubs. Unfortunately, the lower brush had grooved the ring pretty bad so I think a new alternator is in my near future. I cleaned it up a little with crocus cloth and put it back together. I pushed the brush block as close to the rings as I could before tightening the screws, and it is behaving well, but I'll be watching for a good deal on a new one. I figure I might get another 10,00 miles out of this one if I'm lucky.
 
yuppiexj said:
My ND in the 94 just died at 242K miles.

I'm too lazy to spend the extra 2 minutes cracking open the case to change the brushes, I'm just swapping in a new one.
Click to expand...
UPDATE:

The last bits of the brushes fell out when I pulled the alternator free.

<rant>
What F'in moron changed the mount for the ND alternator?
I can swap the DELCO unit in my RENIX in about 10 minutes (including getting the tools).
A couple bolts, couple wires "bam" you're done.
For this version (94) I ended up removing the fan and shroud to get enough clearance to drop the alternator from the bottom side.
</rant>

What can I say? I'm a fan of cheap internally regulated alternators that an idiot (me) can change in a parking lot with a crescent wrench and a pair of pliers, on his lunch break.

Yup
 
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