I have decided to repair the alternator on my 2000 Honda Odyssey. The bearings are smooth. I removed the back cover and the brush holder dust cover. There was what appeared be a mixture of maybe a little grease and mostly of course (carbon/graphite from the brushes). I expect to see dust instead. I wonder how much longer the bearings will go. BTW, I noticed the language in the adv material for the Denso rebuilt alternator suggests that they reuse the original bearings and lube them. Am I OK with just cleaning everything up and just installing the new brush holder assembly ?
Denso alternator repair - brush replacement
- Thread starter rkpatt
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I would purchase a Japanese OEM bearing since it's open. We are on BITOG and OCD! Do it right. But, your vehicle. Do as you wish. According to my mechanic brushes and bearing are common failures. Most rebuilders use Chinese parts when replacement is necessary.
I did a bearing replacement on a Toyota (DENSO) alternator several years ago. I replaced the damaged one in the car with a DENSO rebuilt alternator and changed the bearings on the damaged on since it had a loud squak while the engine was running. I relplaced the brushes as well and used a shop press to press out/push in new bearings.
If you don't have a press don't bother just do the brushes. The likelihood of the bearing going bad this far out is highly unlikely from the units I have seen with high high miles.
Can you re-pack the original bearings?
Can you re-pack the original bearings?
Before you go too far buying parts, disassemble and see how much copper is left on the slip rings. It is not uncommon for the slipring to wear out and then fail the brush.
That gunk suggests slip ring wear. Slip ring repair consists of soldering on a repair ring and then truing on a lathe.
Yes, OE bearings can be washed and regreased. They used Krytox new to deal with the heat and high RPM. It is sold in 2OZ tubes. Expensive.
Rod
That gunk suggests slip ring wear. Slip ring repair consists of soldering on a repair ring and then truing on a lathe.
Yes, OE bearings can be washed and regreased. They used Krytox new to deal with the heat and high RPM. It is sold in 2OZ tubes. Expensive.
Rod
I took another look at the slip rings. The wear grooves are fairly deep but there still copper showing everywhere on both of the slip rings. Since had already purchased it, I installed the new brush holder assembly and put the back cover on. I took the alternator to the chain auto parts store for a test and it checked out fine.
However, it looks like it is not worth gambling on its longevity due to the old bearings and heavily worn slip rings. The R&R of this alternator is not easy. I will purchase a Denso remain alternator.
- Thanks
"Re: Denso alternator repair - brush replacement [Re: rkpatt] #4902362 10/22/18 01:02 AM
ragtoplvr Offline
Joined: Jan 2015
Posts: 647
missouri
Before you go too far buying parts, disassemble and see how much copper is left on the slip rings. It is not uncommon for the slipring to wear out and then fail the brush.
That gunk suggests slip ring wear. Slip ring repair consists of soldering on a repair ring and then truing on a lathe.
Yes, OE bearings can be washed and regreased. They used Krytox new to deal with the heat and high RPM. It is sold in 2OZ tubes. Expensive.
Rod"
However, it looks like it is not worth gambling on its longevity due to the old bearings and heavily worn slip rings. The R&R of this alternator is not easy. I will purchase a Denso remain alternator.
- Thanks
"Re: Denso alternator repair - brush replacement [Re: rkpatt] #4902362 10/22/18 01:02 AM
ragtoplvr Offline
Joined: Jan 2015
Posts: 647
missouri
Before you go too far buying parts, disassemble and see how much copper is left on the slip rings. It is not uncommon for the slipring to wear out and then fail the brush.
That gunk suggests slip ring wear. Slip ring repair consists of soldering on a repair ring and then truing on a lathe.
Yes, OE bearings can be washed and regreased. They used Krytox new to deal with the heat and high RPM. It is sold in 2OZ tubes. Expensive.
Rod"
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I did NOT have great experience with Denso rebuilt purchased via ebay [1999 Odyssey]. It gave me only few years before needing replacement again where as original Denso lasted excess of 15 years! Given that you have already removed yours, just go ahead and reuse yours rather than getting a rebuilt one. There is a good chance that the one you purchase probably had only brushes replaced too along with shiny new paint on the enclosure.
Vikas - I am kind of torn on what to do but need to get the vehicle back on the road. So those Denso rebuilt units (buy at Rockauto or Amazon) are all that good ? The only other options for me taht I am aware of are the more questionable Parts store remans ((AAP - Carquest, etc) or the a one made China ( TYC, DB, etc).
Since the alternator is fine I would drive it as it is and then worry down the road if it's not charging. You might put on substantial miles between then and now and not even need it if you decide to scrap the vehicle or it's in an accident. I wouldn't buy another alternator.
Slip rings themselves can be replaced as well.
Having said that I would just replace the brushes and use the alternator, and not worry about it.
Having said that I would just replace the brushes and use the alternator, and not worry about it.
My guess is the dust from the wear of the brushes formed concretions in the brush holder/slip ring area. I rebuilt one exactly like this one yesterday off my 1999 Accord. Due to press fit bearings and tight fit of bearing on slip ring end, this is not an easy alternator to rebuild. I have years of rebuilding experience, and although a bit rusty at it, I was challenged. Made a mistake and almost ruined the stator. Not a simple alternator for a rookie to learn on. Brush holder replacement yes, but further, no.
If it is difficult to install, you made a good decision to replace it.
If it is difficult to install, you made a good decision to replace it.
Originally Posted by rkpatt
Vikas - I am kind of torn on what to do but need to get the vehicle back on the road. So those Denso rebuilt units (buy at Rockauto or Amazon) are all that good ? The only other options for me taht I am aware of are the more questionable Parts store remans ((AAP - Carquest, etc) or the a one made China ( TYC, DB, etc).
Since the brushes are carbon and the slip ring is copper, generally speaking carbon wears out comparatively lot faster than the copper. You should be able to get two sets of carbon before the copper will wear off.
Forget the chinese built parts store alternators completely. Denso rebuilt are better but still nowhere near the OEM Denso quality. You have the skill to replace it again if it dies on you which although very unlikely.
Vikas - I am kind of torn on what to do but need to get the vehicle back on the road. So those Denso rebuilt units (buy at Rockauto or Amazon) are all that good ? The only other options for me taht I am aware of are the more questionable Parts store remans ((AAP - Carquest, etc) or the a one made China ( TYC, DB, etc).
Since the brushes are carbon and the slip ring is copper, generally speaking carbon wears out comparatively lot faster than the copper. You should be able to get two sets of carbon before the copper will wear off.
Forget the chinese built parts store alternators completely. Denso rebuilt are better but still nowhere near the OEM Denso quality. You have the skill to replace it again if it dies on you which although very unlikely.
About month after replacing the the brushes/ holder, the alternator is not putting out voltage again. Maybe the slip ring area was too far worn. It is time for a replacement. I guess that will I order a Denso rebuilt alternator from Rock Auto vs the other options. - Thanks
Originally Posted by rkpatt
About month after replacing the the brushes/ holder, the alternator is not putting out voltage again. Maybe the slip ring area was too far worn. It is time for a replacement. I guess that will I order a Denso rebuilt alternator from Rock Auto vs the other options. - Thanks
That's too bad. Good luck with the next one.
About month after replacing the the brushes/ holder, the alternator is not putting out voltage again. Maybe the slip ring area was too far worn. It is time for a replacement. I guess that will I order a Denso rebuilt alternator from Rock Auto vs the other options. - Thanks
Thanks for the update!
Originally Posted by Vikas
Forget the chinese built parts store alternators completely. Denso rebuilt are better but still nowhere near the OEM Denso quality. You have the skill to replace it again if it dies on you which although very unlikely.
Denso's slip rings are actually a solid copper end piece that's pressed onto the alternator's rotor shaft, while the aftermarket simply resleeves them with an inferior copper sleeve and plastic bushing. They also install new bearings but they are a little different than the OEM unit. I'd still use one with confidence.
Forget the chinese built parts store alternators completely. Denso rebuilt are better but still nowhere near the OEM Denso quality. You have the skill to replace it again if it dies on you which although very unlikely.
Denso's slip rings are actually a solid copper end piece that's pressed onto the alternator's rotor shaft, while the aftermarket simply resleeves them with an inferior copper sleeve and plastic bushing. They also install new bearings but they are a little different than the OEM unit. I'd still use one with confidence.
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