Hey Gang,
I've been dealing with some alternator issues in my 1990 accord.

The first failure
The first time the alternator went dead, I happened to be on a week long break from work, so I didn't need it immediately. I pulled apart the casing that covers the regulator and BAM. This is what I found.


So I ordered a new brush and installed it. The car ran pretty well for a couple weeks. Then the alternator light came on again.

Round two . . . fight
I pulled apart the casing again, and found that there weren't really any issues with the brushing. At this point, I realized that my power steering pump had been leaking on the alternator and I decided that the liquid filled windings were probably giving up. So I took out my newly replaced brush and went to the local pick and pull to get another alternator.

I picked up the new-to-me alternator along with a new power steering pump and installed them the same day. Everything seemed to be working great!

Third time's the charm
This time the car seemed to run well for about a month. Then for a week, I intermittently had the alternator light coming on. I would check the voltage while running and when the light was off, seemed to have pretty normal readings, but they were a little bit volatile. I think it hovered around 14.3 and 14.5.

Eventually the alternator seemed to go full derp, and my car broke down on the exit to my house on the way home from work last Friday.

Well, I decided to go ahead and pull apart the casing again (mostly not wanting to do a full reinstall.) I found that the brushes in this new to me alternator were quite ground down, but not at all burned up like the prior brush pictured. You may recall that I kept my new brushes from the first failure, which I installed. I also cleaned up the regulator in case it was having any issues getting good connections.

I also noticed that the alternator belt had a little more give than it should and so I tightened it up so that it had about an inch of give on the run (my alternator belt bypasses the AC compressor since my AC system is shot.) I read somewhere that a loose belt can cause an alternator to run hot? Since doing this work, the alternator has given a consistent 14.65 - 14.66 when the vents and lights are off.

Conclusion
Anyway, I'm concerned that this is becoming a habit, and I don't want to be constantly replacing alternators. I started to think, maybe my fans aren't engaging appropriately causing the alternator to be exposed to too much heat. That led me down a two day rabbit hole that I think has me convinced that my fans are working fine (see other posts.)

I had my battery tested at autozone with their load tester based on the cold cranking amps, and they said it's a good battery. I added some extra engine grounds for good measure (I read somewhere that poor grounds can cause issues with alternators.)

Is there anything else I might be missing that could be causing my alternators to go full seppuku (samurai suicide)?

 

I drove the car about 50 miles this morning and this is what my IR thermometer reads on the alternator casing right by the brushes (300 degrees F). Is this a normal temp? If not, what's probably causing it?

I'm considering maybe it's the bearing? Or maybe the pulley size on my alternator? Somewhere I read it could be a grounding issue too?

please help, I don't know what to test next.

 

is this a denso alt? you want made in japan parts.

https://honda-tech.com/forums/honda-...civic-3114911/

 

Yes, it is a denso. This is the part I picked up. DENSO ALTERNATOR BRUSHES / BRUSH HOLDER REBUILD KIT parts Toyota Honda repair | eBay

I sent the seller a question asking if these temperatures are normal since they claim their items meet or exceed OEM specs.

 

Update: the seller said "I dunno" pretty much. They had no idea what temperature is normal for the alternator to operate at, and they said they'll take it back since it's still under warranty.

I also looked into rockauto and couldn't find any alternator brushes for sale there.

 

As mentioned prior you need to try new OEM parts. Seems like you are just mashing parts together here.

 

Raf, I think that's a little extreme to say I'm "Mashing parts together." I found a compatible part that stated it's OEM spec and everything is working well, I'm just concerned about the temperature. If you think it's because I didn't buy directly from Honda, then you can just say that, but it's a bit harsh to treat me like I'm just throwing crap together and hoping it runs.

And I'm open to looking at OEM parts, but the prior poster said to check rockauto for genuine Japan parts, but they don't have any brushes. Do you have a suggestion on where to find OEM?

 

this one sounds decent for a lot less $$:

DENSO ALTERNATOR BRUSHES / BRUSH HOLDER REBUILD KIT parts Toyota Honda repair | eBay

 

Thanks Tamboo! So are you saying you think I need the amazon one? Or are you saying the ebay item (which is the one that I bought and installed) should be good enough?

 

ebay ad says meets or exceeds oem spec so seems ok imho.
i'm running a similar unit with no issues for about 2 years.
alt has about 180k miles at this point. brushes are good for about 160k
in my experience but some other folks get more than that. ymmv.

 

It's likely the bearing causing it to overheat. You should just replace the bearing. If it were me I'd replace both bearings but normally only the bearing closest to the pulley needs to be replaced.

 

Thanks Tamboo and Holmes!

I've considered the bearings. Maybe that's my best option. The place I bought the alternator from has it warranteed, but it's a pick and pull yard, so getting a replacement is contingent on whether they have a car in stock that I can pull the alternator from. Plus, there's no assurance that the bearings in the "new" used alternator are any better! ha ha

I mostly tried the brush because the old brushes were worn WAY down, and so I thought there was a chance that was an isolated issue with the used alternator brushes being near death. I didn't want to pull out the alternator again if I could avoid it, but I feel more confident about replacing the alternator again than I do about doing any bearing replacements. Plus it might be cheaper since the yard I pulled it from will let me go pull another for free. I'm just not sure if the next one I pull is going to have similar issues.

Maybe the lesson here is that alternators aren't great to pick up from a junkyard like I did?

 

the lesson as i see it is find a denso unit.
if you cant afford new then inspect and rebuild if necessary.
inspect again after 160k.
the end. 8)

 

Thanks Tamboo! The unit I grabbed from the car in the pick and pull yard is actually a Denso unit.I think I just need to decide whether it's worth doing the bearing, or whether I should roll the dice a little with another Denso from the yard. I suspect they'll have a couple there.

 

this is cool that u rebuild your alt rather then just buying someone's rebuilt one keep up the good work

 

Thanks! Honestly, it's easier to drop a new set of brushes into the alternator than to replace the whole thing. It's like 4 small nuts and off comes the case, then 3 or so screws to pull the brush. It's easier IMHO than pulling the power steering pump and both belts, then pulling the alternator (which I've pulled my radiator fan to get to in the past). But I'm thinking I'm probably going to head to the pick and pull yard soon and have them make good on their warranty. I'll probably end up doing the full alternator again. I think the bearings are more expensive on rockauto than I paid for the whole used alternator.

 

lol i saw a voltage regulator on rockauto for $175!
about $25 more than the entire alt plus core charge...

 

rockauto has bearings for $18, with shipping and 5657529945519067 discount code it's $20. I can't imagine that being any worse of a deal than taking a chance on a junkyard one...since you already swapped out the brush.

 

You're right, that's not too bad. I was thinking I'd need to buy two bearings (commutator end and drive end) which I thought would be about 20 a piece. If alternators that have sat for a while are more likely to have bearings issues, maybe you're right that it's better to just go ahead and do that.

I've never actually replaced a bearing or bearings for an alternator, How do you determine which bearing needs replacing? On Rockauto they have two different listings for commutator and drive end bearings, but then in each description they say "drive end" see below. So I don't know whether I need two, or just one. And if I recall, isn't there a special tool needed to do a bearings job right?


In any case, I guess I better get searching for a good DIY on bearings replacement. I think I paid 35 for the junkyard alternator, and I could go and get another for nothing, so it's just a matter of whether there's a chance that a junkyard alternator would be good to go if pulled. (honestly I'd probably put the old worn brushes back in the current junkyard alternator before returning it to the junkyard so that I would have my practically new brushes in case I needed them.)

Thanks a bunch for the coupon code, that will come in handy whether or not I end up doing the bearings!

 

Right?! I CAN'T imagine they sell too many of those. That blew my mind too.