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Discussion Starter · #1 ·
Howdy Sonata Forum - Last night my battery warning light came on. I immediately suspected the alternator. My sonata (2002 2.7L V6) has 172k and has what I am pretty sure is the original alternator. I'm thinking the alternator has been living on borrowed time. I almost replaced it about a year ago but the battery light was intermittent at that time and it went out on its own. This time I am afraid I will not be as lucky. On the drive home last night if I kept the RPMs above 4k the light would go out. Around 4k it would flicker. At about 3500 or below it would be on solid. I got home OK. Luckily the battery is not that old. This morning I put a multimeter on the batter and got about 12.4 volts. After starting the car the voltage dropped to the high 11's. I could get it to kick up a little by revving up the engine but clearly the batter was not being charged. I checked some connections but they seemed to be OK. I took a deep breath, said a prayer or two and commenced to remove the alternator. That is not an easy task. I know there is some controversy as to whether the alternator should come out from the top or bottom. Mine came out from the top. It hugged the firewall all the way up and took some twisting and turning. It is now sitting on my workbench. It is a valeo model SG9B025. I am pretty sure that the problem is the brushes. There is not much brush left. Like I said, we're talking 172k miles here. So now the question is do I just replaced the brushes (assuming I can find them) or the entire alternator? What I find kind of amazing is that searching for alternators using Hyundai is kinda expensive. A rebuilt one from the auto parts store is $150 and up. On the other hand searching using the valeo part number shows brand new ones on ebay for $119 including shipping!!

Alternator for Hyundai Santa FE Sonata Kia Magentis | eBay

I took some time to clean up the round thing (not sure what it is called) that the brushes sit up against. It is nice and shiny now.
So I am still trying to decide if I should change the brushes or go for a new alternator. I'm also wondering if I should take it to a local electrical motor place which might have the brushes I need and which could test it for me after replacing the brushes (although I think I could replace the brushes on my own - again assuming I can find 'em). I welcome any advice or thoughts from folks who have been down this road. I am attaching some pics for reference. Thanks in advance!
 

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TSB 03-36-020


DESCRIPTION:

A new generator is available for the 2.7L V6 Engine. The changes to the generator are:

The generator pulley size (as measured to the top of the belt grooves) has been decreased from 62mm (2.44") to 58mm (2.28"). This results in higher generator speed and output at engine idle.

The voltage regulator's temperature compensation has been changed to lessen the drop in generator performance as the temperature increases.

The part number of the generator has changed.

These changes result in improved generator performance at low engine speeds.





Other than the different labels and pulleys, the generators look the same.

As a result of the change in the pulley size of the generator, the serpentine belt has also been changed, as outlined in the table below.

The new belt is approximately 5mm (0.2") shorter than the previous belt.
25212-37181 = new belt

-----------------------------------

Slip ring in your pic is beyond toasted,, brush not going to help... you into replacement alternator.
 

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Discussion Starter · #3 ·
Hi SBR, I know you know what you are talking about. I'm going with your advic

Ordering from HyundaiOEMparts.com:
Part Number was superceded!
Quick Order
Old Part Number 37300-37250
New Part Number 3730037405
Part Name ALTERNATOR ASSY
MSRP $360.81
Core $0.00
Online Price $288.65

Old Part Number 25212-37181
New Part Number 2521237182
Part Name V-RIBBED BELT
MSRP $26.18
Core $0.00
Online Price $20.94

Please tell me though, what did you see in the slip ring that made you believe it was toast? I'm thinking it was the bottom part being worn down in the middle from the lip (see pic). Is that what you saw?

Thanks
 

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The slip ring closest to alternator body has a severe groove cut in it from the old brush..

The rings were flat when new, and same diameter. The top one has minor wear (see slight groove),,, and the other looks somebody run a lathe cutter on it and made a deep groove.. putting new brush on it likely just tear up new brush pretty quickly
 

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Crappy materials. Is not normal for ring to wear more than the carbon (graphite) brush. Ring it shouldn't be copper, it should be some kind of brass.
 

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Crappy materials. Is not normal for ring to wear more than the carbon (graphite) brush. Ring it shouldn't be copper, it should be some kind of brass.

Pretty std practice for slip rings to be copper.. copper can run from soft to gilding (not sure if proper wording), which is a lot harder.
 

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Discussion Starter · #8 ·
Well the alternator replacement is complete. The battery light is out and the multimeter shows the battery being charged. The total cost of a new alternator and serpentine belt was $359.13 delivered to my door. Seems like quite a bit but I am glad that I replaced it. The alternator is not easy to get in and out of there and I would hate to try to rebuild it, find out something went wrong and have to remove it again. My sonata has been very good to me over the years and has kept me out of car payments for almost 10 years now. I think a new alternator ended up making sense cause I'm planning to keep this car till I'm riding on the chassis. Hopefully this alternator will go for 172k miles like the original one did. Attached are some pics showing the back and front of the old and new alternators. Like SBR said the new part clearly has a smaller pulley. New serpentine belt is on there nice and snug.
 

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yea, I cringe when EF alternator replace come along and I get stuck with it.. seems axle partial remove and engine/down makes for a hole for alternator to come out wheel well.
 

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Oh, that's how is done on 2.7L? On my 2.5L V6 Sonata EF I managed to take it out to the top of engine. Tight, but it worked.

Only on my Sable (3.0L V6) I needed to take it trough passenger side wheel, but I left the axle in (just disconnect the outer tie rod to allow hub to rotate to the max).
 
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