Source for fiber washers/insulators in alternator

79Vette

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I am trying to rebuild a failed alternator on my M1009, and an having a hard time fining the parts. I bought 2 "rebuild kits" which were allegedly for isolated ground 27SI alternators and specifically listed the M1008/M1009 as compatible applications, but they are missing a lot of critical parts.

Left to right in the attached image are the ground stud, a small stud that was not externally connected (sense terminal?), and the positive stud. My kits came with a replacement postive stud and insulators (which I have installed), but the kit does not have either of the other studs or their insulators. As you can see my hardware is badly corroded and the insulators are partially eroded, and they need to be replaced. Does anyone sell these parts?

I've bought parts from ASP in the past, but this is the only hardware I can find for a 27SI and it does not contain any of the parts I need.
https://www.aspwholesale.com/alternator-parts/delco/hardware-kits/hardware-kit-p12660.html


EDIT:
I ordered 93785A300 and 93785A817 PEEK washers from McMaster Carr. This should get me up and running, assuming they show up tomorrow.
https://www.mcmaster.com/spacer-washers/material~plastic/for-screw-size~no-6/

But if anyone has a source for the correct fiber washers, plastic insulator and rubber cap for the sense terminal, and the B- stud and insulators at a reasonable price I would love to know where to get those parts. I did find the sense terminal hardware here but shipping is $20...
https://iglobalparts.com/new-kit-co...l-6786-49-1511-120-12073-500-12142-120-12014/
 

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cucvrus

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Or a hardware store. Also a starter and alternator shop can take all the guesswork out of this job. There is a lot more to rebuilding components to last then replacing a few parts. Good Luck.
 

MarcusOReallyus

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It's been quite a while since I've been inside my alternators, but IIRC, the insulator is not just a flat washer. One side has a collar that fits in the hole. That way the screw can't migrate to one side and contact the metal housing.

But I might be wrong on that. (Hey, it could happen!) ;)


I've never encountered a carbon fiber washer before. Carbon is usually conductive. How are the washers?
 

79Vette

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The PEEK washers from McMaster arrived, and fit nicely. I prefer to use original parts where possible, but these will be as good of an insulator as the original parts and should last for many decades.

As a follow up question, neither of my original alternators had a resistor across the terminals of the brush holder. However, the parts kit included one and several threads on this forum show them. See photos in Post 1 here:

Were my alternators improperly serviced before, or is there some reason this component should be omitted?
 

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dependable

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I've worked on many of these alternators, and have seen them with and without resistors. This manual refers to them being in "some models."

I would be interested in knowing resistor's function, I just put the alternators back together the way they were, resistor or no resistor.

Usually when I fix them, I replace only non-functioning components, usually the diodes or voltage regulator, once in a while, the rectifier. The reason I don't replace everything even though I have the parts is I believe the original parts to be of higher quality than available aftermarket ones. As shown in manual, most components fairly easy to test. I know the original bearings are higher quality, so if they don't make noise, I leave them.
 

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dependable

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Still wonder why resistor was put there, must be for some reason, even if it is not needed. Radio noise suppression ( as in car radio) ? I know I've seen the resistors in civilian Delcos also.
 

Tow4

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No, the resistor is between the trio and ground terminal. The trio provides the voltage to operate the regulator. The resistor either has something to do with exciting the regulator and/or turning on the dash light in certain applications, I would have to look it up because I don't remember the details.

If you want to suppress noise in an alternator (they produce alternating current until you rectify it, hence the whine you hear in the radio), you use a capacitor.

 
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