replacing bearings in alternator

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How many out there ever replace the bearings in an alternator when they get dry?Most people just replace entire unit,right?
 
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I would turn in the core (worn alternator) and get a discount towards a remanufactured one from Audi. My A4's alternator is over 180 miles old. I'm somewhat worried. My previous cars all had alternator issues within tens of thousands of miles. The only thing that really wears out on alternators in my experience are the brushes. Those can be replaced (often need to be soldered in). However, as I said, I'd go with a remanufactured unit.
 
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99.9% of the time the entire unit gets replaced. Only dedicated DIY's, and I consider myself one, will buy an alternator rebuild kit and rebuild the alternator themselves. The rebuild kits come with not just bearings but also brushes and the voltage regulator. If the commutator is worn out then you end up having to go to your local rebuilder anyway to take care of that problem.
 
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I, of course, have a different opinion here. I have had plenty of problems with remanufactured alternators and would actually consider replacing the bearings myself - that way you have a known entitiy. I did that on an AC Delco alternator on my Jeep when the bearings went around 150k miles. it was still running at 200k. besides, a reman unit will cost you over $100. now, when I had to replace the starter on my LH, I actually poppped for a new, genuine DC starter, especially since I had to unbolt the motor mounts and lift the engine to get the starter out.
 
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It is a huge waste of time and money to replace the bearings and most shops will tell you this.The better way is get a high quality reman alternator instead saving time.
 

gonzo

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Waste of money?Thst's interesting.Waste of time?I'm the most unmechanically inclined person in the world and it takes me about 10 minutes to take an alternator off.Maybe I'm just a cheap wad!
 
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northern Alabama
 Originally Posted By: moribundman
I would turn in the core (worn alternator) and get a discount towards a remanufactured one from Audi. My A4's alternator is over 180 miles old. I'm somewhat worried. My previous cars all had alternator issues within tens of thousands of miles.
Do you mean 180k miles?
 
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 Originally Posted By: wafrederick1
It is a huge waste of time and money to replace the bearings and most shops will tell you this.The better way is get a high quality reman alternator instead saving time.
A shop will tell you that because they can't rebuild the unit in shop for the price of a reman and they don't want to chance a comeback. Besides that shops these days are mostly parts-changers, good old-fashioned mechanics that could fix anything are going the way of the dodo bird. A dedicated DIY'r that is willing to tinker has nothing to lose assuming parts are readily available. What is the alternator from?
 
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I would rather buy an new reman with a warranty, as doing my own R&R may not replace all the worn parts. I recently had my alternator take a dive, with about 85K miles on the car. Since I needed to fix the car the same day, my only option was replacing it... If I would have been able to keep the broken one, I would have gladly done a home rebuild just for fun. That said, I had an interesting failure, where the pulley detached from the alternator....it didn't fall off, it would just spin on its own without turning the alt...even though all the bolts were tight. Me thinks all my high RPM driving and constant shock loads did a number on the factory unit.
 
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I open all mine up before going to the auto store to assess the condition. If the model is known to be reliable, looks good, and the parts are cheap I just replace bearings and brushes and run it again. I'd rather rebuild the one I have that is in good shape than take a chance on getting a just above reject rebuild for my good one. If there is irreparable damage in the stator, rotor, case, brush contacts, or the outrageously priced (GM) regulator has a known short life I let the rebuilders have it and hope that I get an above average rebuild in return. The quality of some rebuilds is low enough that you should expect to rebuild the rebuild. I at least open mine up and fix what they missed, like anti-seize on threads. Bearings are on eBay and Advance Auto can next morning delivery many brush sets. Be sure to buy 16,000+ RPM bearings which is the sort of thing you learn after doing it wrong a few times. The el-cheapo bearings will warp the seal from the heat, spit the grease, and die quickly. I've gotten to where I rebuild my own idler pulleys because I don't like the el-cheapo bearings that some suppliers use. Warranty or not a failure every 6 months is unacceptable. The real value in DIY is that if rebuild parts are cheap enough you can do it more often than necessary and never see a failure. Many parts like alternators and brakes have a predictable life span and trying to eek out every bit of the last 20% of the life will cost you more than the first 80%. Work on the car at your convenience and for $20 throw the parts away a bit early and save yourself the grumpy driver pick up, the cost of a tow, and the supersize service bill because you were away from home and couldn't fix it yourself.
 
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 Originally Posted By: severach
I've gotten to where I rebuild my own idler pulleys because I don't like the el-cheapo bearings that some suppliers use. Warranty or not a failure every 6 months is unacceptable.
Where do you get the replacement bearings from? Is your local bearing supply shop able to match up the old bearing?
 
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A related question: who sells the best rebuilds? I haven't bought a rebuilt stater or alternator in a long time. If I had too I'd probably go to Napa.
 
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Autozone's duralast line of starters and alternators are fairly good IMO. have a starter from them on 2 (well one now because I sold the other one yesterday) of my cars, and have had 2 of their alternators. Most of the bearings unless trashed have manufacturer number on them, so they can be cross referenced.
 
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 Originally Posted By: pzev
Me thinks all my high RPM driving and constant shock loads did a number on the factory unit.
on the police interceptor crown vics ford has a one way clutch on the alternator pulley for just that reason.
 
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 Originally Posted By: bdcardinal
on the police interceptor crown vics ford has a one way clutch on the alternator pulley for just that reason.
Saab has the same setup on the 93. They call it an IDP, isolator decoupler pulley. link
 
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My alternators use 6203, 6303, and 6204 bearings which are easy to find. Unfortunately the only ones I could find cheap locally were low quality mower bearings which can't take the heat and RPM of an alternator so I bought from eBay. RBI/RBTech seem to have the specs at a good price.
 
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Grainger was able to get me 6203 and 6303, 6L025 and 6L052 is their stock number. Both are NTN, double-sealed and filled with Chevron or Shell urea-base grease. My idler pulley and my alt are riding on Grainger-sourced bearings, I was shocked that Delco-Remy who remaned my Denso alt used cheap Chinese bearings in it - my brushes were worn caused the idiot light to turn on.
 
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