3B Alternator Alternatives (1 Viewer)

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Jun 12, 2010
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So I've been slowly gearing up for a rebuild for a while, figuring that with my old alternator having failed and a garage big enough to do the job, I may as well. It's a 1980 BJ40 with a 3B in it, 12v. Part of that rebuild is, of course, dealing with the alternator. My old one gave out, so I found a used one from Canada. It sat on a shelf for a while, but since I've finally got a bit of time, I decided to haul it down to a local alternator shop to figure out the best way to clean it up, have it tested, and get some advice on machining corrections for the mount ear holes, which were in bad shape, and maybe see how much a rebuild would cost.

They flatly said that it'd be pretty much impossible for them to rebuild it -- they just can't get the internals. Furthermore, as soon as the main repair guy picked it up, he noticed that the shaft was loose enough to knock around -- evidently, the bearings are well on the way to being completely shot.

So now I'm left with a problem. My vac pump is a coarse spline model, and I can't get a new alternator in anything but fine spline models. That means I'd need a new vac pump, which I understand is hideously expensive. I've also heard that electrical vac pumps are an option. So is there anything else I could try? If not, what would you guys suggest for replacements, vac pump & alternator wise?
 
What's wrong with the "old" one?
What do they mean if they say they can't get the internals?

Rudi
 
I used a Isuzu npr truck alternater works great same vacuum pump 70 amps as opposed to 55 the Toyota had
 
What's wrong with the "old" one?
What do they mean if they say they can't get the internals?
Rudi

Evidently they can't source the bearings/seals needed, since it's an older coarse-spline model. Guessing they don't share the same seals as the fine spline ones do, for whatever reason.

I used a Isuzu npr truck alternater works great same vacuum pump 70 amps as opposed to 55 the Toyota had

Straight bolt-up solution? Are they still in production (or at least all the parts needed to rebuild them)? This work for the coarse spline vac pumps, or just the fine ones?
 
Where are you located? There is a fellow in Abbotsford, B.C. who has rebuilt alternators, EDIC motors and starters for me for the Land Cruiser.

He is just off the #1 at McCallum Rd. in Abbotsford behind the Esso station on the north side of the highway. The fellows name is Nathan Unger. If it can be fixed he can fix it!!
 
That means I'd need a new vac pump, which I understand is hideously expensive. I?

Whats hideously expensive mean?
 
The PO that installed the 3B in my 60 went with an electric vacuum pump and some unknown alternator. When I had to replace the alt I was able to fit one for a 2F just fine. Oriellys part 14315, $63.

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a bearing is nothing special ...just get the dimentions

I am not sure about the seal, but use a micrometer, measure inside dia outside dia and depth, then call a couple of bearing places that sell sealed ball bearings with those dimensions and they should work for you.

Evidently they can't source the bearings/seals needed, since it's an older coarse-spline model. Guessing they don't share the same seals as the fine spline ones do, for whatever reason.



Straight bolt-up solution? Are they still in production (or at least all the parts needed to rebuild them)? This work for the coarse spline vac pumps, or just the fine ones?
 
I second cruiser_guy 's comment. Nathan at ASI rebuilders is awesome. He isn't cheap, but he is one of the best.
I'd be interested to hear more about the NPR truck option as well, what's needed to make it work?
Other options just include stuffing almost any alternator in there and running an electric vacuum pump. Likely need a custom bracket.
 
cool but...wonder what shipping cost is to Vancouver Canada? I bet I can pick up two, and sell them both.

on the otherhand, the npr alternators are a really good price!!! is this a bolt in for the 3b?
 
I found this while searching:

https://forum.ih8mud.com/showpost.php?p=5906348&postcount=6

But before I found that, I encountered the same situation.
My rebuild shop wouldn't rebuild mine either, I have a damaged spare I wanted to rebuild. the currently installed one is fine now, but when failure comes (or I finish several other projects) I'll probably rob pieces from the spare, or start my alternator conversion and I've got some parts waiting on the shelf.

I picked up a recently reman'ed large case Ford 3G alternator that puts out 130amps for $50 from a junkyard. And a belt driven vac pump from a 1996 Ford F-250 7.3L from Rockauto.com for about $70 USD. I like that this solution separates the two functions of the stock alternator so if one function fails I can replace or rebuild it quickly.

I didn't like the electric vac pump options available, since all the good ones were as expensive as replacing the stock alternator with the same thing, only brand new, or the reviews of cheap ones I found made me question how long it will last and I don't want to wonder when dealing with brakes. I plan to mount the vac pump low, under the fuel pump, and the alternator in the stock location.

With some time into fabbing up new brackets and putting a new pulley on the ford vac pump, I'll end up with two easy to replace parts and the Ford 3g will put out more than double the amps in stock form, I can rebuild it for $30 and put a 160amp stator in it for another $25, which makes charging a whole lot faster after any use of the winch.

If you've got the engine out for a rebuild anyway, fabbing up brackets would be much easier.

I thought I'd seen some pictures of the vac pump installed, but couldn't find them here.

Rollinns
 
Well I ordered the Isuzu NPR one from Ebay, for that price I'm willing to experiment. It will be a while before I can use it though so don't look for a quick feedback. I'll take some pics and compare it to the 3B one.
 
i made a new mounting bracket for the npr alt just mocked it up with the alt i think the 3b bracket was to wide
 
Anyone ever confirm if the NPR alts work fine with nothing more than a different bracket? Is it possible to modify existing brackets to fit, or does it really require an all new part? Little wary about just trying to make a new mount since I've never done that before, and the last thing I want is a critical mount failure.
 
Anyone ever confirm if the NPR alts work fine with nothing more than a different bracket? Is it possible to modify existing brackets to fit, or does it really require an all new part? Little wary about just trying to make a new mount since I've never done that before, and the last thing I want is a critical mount failure.

To answer your question, it will work but it's not a drop-in simple change. The pulley is different. The NPR style is internally regulated while your Cruiser's alternator might be externally regulated which requires some relatively simple wiring changes. And you'll need to make a new bracket.

You get more current out of the NPR alt and you can buy them at most auto parts stores anywhere in North America. They are used in the GMC-branded NPR box trucks too.
 

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