Can't Find Alternator


YJYJ94

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My alternator is not working and I need a replacement. However, when I go to all the autopart stores the alternator they give me does not match what I pulled from my 1990 4.2L Jeep Wrangler. They seem to be the same design in general, but the holes for the bolts are in the wrong places (they are turned 180 degrees). Also, mine has 5 grooves in the pulley and what they give me is a single groove. I just bought the jeep a month ago and I don't know if the alternator is stock or perhaps it's from another year Jeep. Any help would be appreciated. I included pics of what it looks like.

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Gilaguy23

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I can see a factory part # stamping on it sorta. See if you can decipher it 100% and try the likes of a good hard parts auto store like some Napas. Places like Autozone,Oreileys etc are worthless trying to match parts off knowledge. If that dont work find a rebuilder or do it yourself.
 
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T-Rex Jeepster

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Maybe previous owner changed over to the later alternator? I have seen others break the case apart and reposition them to fit the bracketry. Pretty sure it will fit 180 degrees out of either position.
 
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T-Rex Jeepster

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I can see a factory part # stamping on it sorta. See if you can decipher it 100% and try the likes of a good hard parts auto store like some Napas. Places like Autozone,Oreileys etc are worthless trying to match parts off knowledge. If that dont work find a rebuilder or do it yourself.
I only use AZ or O'R for minor applications ie. Filters, Fluids, Bulbs etc. Anything over that, NAPA.....We have a NAPA house here that still has 8' of book rack on the counter. And all of the Guys that work there have been since High School. I'm a lucky guy!!
 
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YJYJ94

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Yeah I think I will open alternator and twist the bracket 180 degrees. Worst case I will take the alternator to get it rebuilt. I bought Jeep a month ago and I contacted seller and he said the engine was just not rebuilt, but rather, replaced with another motor that was rebuilt which is most likely why I cant find alternator match.
 
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Gilaguy23

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Your not the first one to post needing an alt and cant find one with the right configuration. matter of fact i think there is another with the same delima posted a few weeks ago. Wish I had the answer for ya. Seems a cross over took place from a single V belt to serpentine in 89/90ish and parts are pretty hard to come by. Dont give up though!!
 
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YJYJ94

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I've used these guys a few times......Been doing rebuilds for over 50 years, Give them a call and maybe you can ship the one to them and tell 'em what you need.

Great! I ordered one from Napa and I will have to rotate housing 180 and add the pulley mine has. Other than those two things, the alternator looks identical. So hopeful...but if it doesn't workout, then I will give your guy a call. Appreciate all the help.
 
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YJYJ94

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Got the biatch running again...thanks to everyone's help! Went to Napa and got an alternator rated for 78 amps. After install, I took it to my uncle (mechanic) just to make sure electrical was correct since voltage regulator wire was cut from harness by previous owner. When he checked the amperage being produced it was making 90 amps. He said when they rebuild the alternators, the internals they put at times create more amps than what they are rated for (good for me).
Sooo...I ended up having to switch out the pulley from the original to the new alternator and I had to open alternator and twist it 180 degrees so I could bolt it on the jeep's bracket. And voila....it started right up and it's charging again. Now for those who have never opened up an alternator like myself there is a trick to twisting the bracket. When you pull off the top half of the alternator two springs and two magnets pop out of their housing since the alternator's shaft is no longer there to keep them in. So when you twist the top half 180 degrees and are ready to put the alternator together, there is no way of doing it since the springs and magnets are popped out. So you have to put something like a paperclip through the holes in the magnets and housing to keep them in place as you assemble the alternator (there is an access hole outside the alternator to do this). Once assembled, you slide the paperclip out to release the spring and magenets. I included pics so you know what I mean. Luckily, I figured it out on the old alternator, otherwise, I would have broken the magnets on the new alternator like I did on the old one. I'm sure many already know how to do this, but hopefully this helps newbies like myself.
Alternator Spring and Maganet.jpg
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YJYJ94

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I fogot to mention that you want to put the paperclip in before you disassemble the alternator, otherwise the magnets and springs fly out. Could possibly damage the magnets.
 

Flyer58

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Good deal, glad it worked out. If you have a good battery and switch all the big lights to LED's you should be well within the limits of the regular amp alternator so now you'll really have it covered.