Alternator Rebuilding.

[George7941]

From my Sierra at twelve years of age with 176K km/110k mi. Alternator is DR44G, GM 10392759. I took the rear cover off to see how much life is left on the alternator. The brush, shown in the picture, looks to have about 30% life left. More worrying to me is that the slip rings are worn down about 12 thou where the brushes ride. The worn surfaces of the slip rings are smooth enough. I could not get a clear picture of the slip rings.

Brushes are cheap enough, so I will install new ones. Think the new brushes will make the alternator last another six years,at which time I expect the body of the truck to be rusting out and I will have to get a new vehicle?

As an aside, anyone know of the origin of this DR44G alternator? I have seen it listed as a Bosch alternator and have also seen it listed as a Delco alternator. I know of no ties between Bosch and Delco. The DR44G seems to be similar to the AD244 alternator. Remy sold their heavy duty alternator division to Borg Warner.

 

[Donald]

If you have an alternator rebuilding guy you can ask him your questions. But those shops are getting few and far between.

There are bearings to consider also. Possibly a rebuild alternator from a local guy would be a better investment.

 

[George7941]

I am leaning towards just replacing the brushes and seeing how long the alternator lasts. I do not think that it failing me would strand me because I check the alternator voltage at least once per trip ( it is one of the four parameters displayed on my ScanGauge). The ScanGauge supplements the stock analog GM voltmeter on the instrument panel. A failing bearing will give me plenty of warning.

 

[Kruse]

Originally Posted By: George7941
I am leaning towards just replacing the brushes and seeing how long the alternator lasts.


I can't really tell because of a fuzzy photo, but how rough are the slip rings? Rough rings will chew up the brushes in short order.

 

[George7941]

The slip rings are pretty smooth , just worn down 12 thou. Since it is smooth I do not expect it to chew up the new brushes. I am expecting the original GM alternator to last for the eighteen years I plan on keeping the truck.

The alternator has a pretty easy life. I do not drive much at night, and with a stick, I do not always have to have my foot on the brake pedal at lights. I hardly ever turn on the blower motor, unlike some I know who always have to have their blower on. No AC, so no current needed to operate the AC clutch. No defroster.

 

[clinebarger]

The DR44G is a Delphi alternator, GM did install some Bosch alternators on GMT800 pick-ups (RPO KW1, 160 AMP), Quite rare & usually on a EMT/Fire/Up-fitted truck.

 

[tomcat27]

I'm sure your bearings are fine; but when my GM alternator bit the dust @ 170k, a bearing seized which took out the serp belt. (just saying that checking your voltage is not a sure test )

 

[djb]

0.012 inch wear -- that's all?

The copper rings are usually quite thick, well over 1 mm. You should eventually look up the spec, but it's likely to be 0.040 or even 0.050 inch.

 

[Johnny2Bad]

Can't you buy an alternator rebuild kit for it? They contain every part susceptible to wear and complete instructions. I would be surprised that a GM alternator doesn't have a kit available somewhere. Last one I bought (for the old-style 65A alternator 1980 GMC Truck) was $20.

 

[George7941]

The days of $20 rebuild kits are long gone. A kit for the DR44G is a hundred bucks.
https://www.aspwholesale.com/alternator-...kit-p12278.html

 

[OilFilters]

Can't say I've ever heard of anyone taking off an alternator before it breaks. I'd look around for a good, well priced replacement and leave it on the shelf until you need it. Leave the other one as is. We don't rebuild things like this in 2018.

 

[mjoekingz28]

When I got my 03, the seller exchanged the alternator from one he had on a c/k truck. I was worried. It did fit, but some pressed in flanges on the alt mount had to be compressed/bent in. It seems to ride true on the belt, but I dont think a factory size alt will fit anymore. It is ACDelco and I removed it, wiped it down with windex wipes (per the guy at Exide....I know OneEyeJack prefers Pledge ) and then took it to a rebuilder before I was getting a multi-amp stereo install. I think it was fifty dollars. Also, when I was courying in my Saturn- I removed the alternator at around 200k IIRC and took it to be rebuilt while it was still working.





At 150,000 a car is probably due for a belt and a new alternator- so find a good time and get a factory belt and have your alternator rebuilt. I hear remans are of poor quality, very expensive, and plus the labor involved in taking it to the parts store, having them ship it to Remy, then having Remy clean,rebuild, and redistribute them seems bothersome- when you could just run it down to the electrical rebuilder and clean your wirings and the exposed areas the removal of the alt revealed. Then pick it up the next day and reinstall.
Should be good another 10 years/150k!

 

[George7941]

Originally Posted By: OilFilters
Can't say I've ever heard of anyone taking off an alternator before it breaks. I'd look around for a good, well priced replacement and leave it on the shelf until you need it. Leave the other one as is. We don't rebuild things like this in 2018.


As you can see from the picture it does not get any easier to remove the alternator than on my truck. It can be taken off in less than 10 minutes, without hurrying. The rear plastic cover on the alternator just pops right off with a screwdriver. Once the brushes wear out and start arcing it will destroy the slip rings, so it is sensible preventative maintenance to replace the brushes before they completely wear out.

 

[dlundblad]

I read the OP as SIENNA as in Toyota then you posted the pic of a 4.3 Vortec.. Left me scratching my head. Thankfully, it's Friday!

 

[racin4ds]

Usually with the GM/Delphi alts we seen DE Bearing failure long before brushes wore out. Most of that was improved in your model DR44G though. The CS130 units used prior were garbage! They kept us rebuilders in business and still do!

Diode failure on the rectifier bridge was another common Delphi weak point. If you have access to one, I'd take a look at ripple current using good scope, see how "dirty" that output is getting..

 

[George7941]

Thanks. The perspective of someone in the alternator rebuilding business is very useful and interesting.

I use a scope regularly on vehicles I maintain to monitor the health of the fuel pump and starter motor. I have never had a diode fail on an alternator, so I have not been monitoring the alternator waveform. I just check the dash voltmeter to ensure the alternator is maintaining adequate charging voltage. Now that you mention diodes are a failure item on Delphi alternators, I will monitor the alternator waveform.