Has anyone rebuilt their alternators themselves?

[Kestas]

I am considering rebuilding the alternators on some of my cars. Many of them have over 100K on the alternators. I'm considering doing this as preemptive maintenance. I don't want to be stranded in an inopportune time as happened once to me.

I also believe rebuilding the original alternator yields a better product (you get to keep the OEM alternator) over buying one already rebuilt, assuming you get quality repair parts. Is this thinking solid? Once done I should be good for another 100K, right?

 

[artificialist]

I never did, and that is because of what happened to one of my friends.

He had an early 1990s Subaru, and the alternator died. The only reman alternator cost over $200 plus a hefty core charge, so he bought a much cheaper rebuild kit.

Unfortunately things didn't go back together as it should have, so he was out the cost of a reman alternator, they wouldn't accept the core that wouldn't go back together, plus he lost money on the kit.

The only thing I would do is have an alternator rebuilt by a specialty shop, or get a reman from the company that built the alternator, or one from the car dealer.

 

[cchase]

I'd definitely consider doing it if I thought it was coming up. I think the diode pack on one of ours is on its way out and I am prepared to replace it when it starts making more noise.

 

[mechanicx]

Some of the later model alternators are harder to get apart and to get replacement internal parts, but some guys rebuild some of the late model alternators. I use to rebuild the older model alternators. Not as preventive maintenance but if and when they went out. They were much easier to take apart and put back together, and parts were readily available. You could often overhaul one that went out for under $5, usually with just a diode trio. Things use to be designed more for overhauling.

I agree with you that rebuilding the original would be better and cost effective, if not time effective, to those crummy aftermarket rebuilds. Plus les money going to china

. You can sometimes get a higher quality OE reman but that's more money.

I think maybe getting the same alternators out of the junkyard at a good price to practice on, for spare parts, and to have repaired and ready to go unit might be a good way to go about it.

 

[NHGUY]

I wouldnt want to spend hours messing with something,potentially messing it up,and then have it fail with no warranty,and money out of pocket.No way.

 

[Donald]

One of the things they do is to "cut" the armature on a lathe where the brushes contact. Will you do that?

They will also check out the output waveform on an oscilloscope.

If its a Mando and its broken toss it.

The good rebuilts replace the diode bridge. The cheap places solder in new ones to replace the broken ones.

 

[Kestas]

The folk that sell the rebuild kits say it doesn't require any special skill to rebuild an alternator. I'd be doing it when the car is retired for the season.

 

[Falken]

I have cracked one open as a part of a Starting and Charging module at school.

We had about 15 alternators for the students to practice on, use a Growler, etc.

The biggest problem was getting the thin aluminum case apart. You have to be very gentle with it and patient, no bashing away at it with a plastic hammer or anything.

They are very easy to break and crack, it is cast aluminum and heavily corroded so the halves stick together pretty good.

Best bet is just to pull it off of a scrapped car in a junk yard.

Your first reman of a broken alternator wouldn't go very smooth, but after doing one, if you had to do the same model you'd figure a way to do it very well. Sadly the one you stick on the car would probably last the rest of the life of the vehicle so it would be pointless mastery.

 

[440Magnum]

Originally Posted By: Kestas
I am considering rebuilding the alternators on some of my cars. Many of them have over 100K on the alternators. I'm considering doing this as preemptive maintenance. I don't want to be stranded in an inopportune time as happened once to me.


I've done it a few times in the past. Its very easy to replace the brushes and polish the slip rings if they're not scored. Bearings are easy enough if you have a light-duty press and a pulley puller/installer. Diodes are a bolt-in part on most alternators, some you have to solder, and it takes a beefy (100-watt class) soldering iron.

The windings don't wear- if they aren't overheated, or the enamel insulation cracked, you're good to go.

The one show stopper would be if the slip rings are too worn to clean up with simple polishing, or if they're worn all the way through. That requires an armature shop's specialized tools.

So barring that one thing, its about the simplest job on a car short of changing the oil. But now... try to FIND the brushes and bearings in the retail marketplace anymore! No one does this, so the market is all but dried up. Its been quite a while since I saw 'alternator rebuild kits' of any quality at all in a parts store.

 

[expat]

Yes, A few times, but I have only replaced brushes and bearings.
It worked out pretty well for me, lasting over 100K miles in one instance.
As far as Diodes go, I'd say 'If it ain't broke, Don't fix it'

Alternators were a Nippondenso from a Toyota 22R and a Lucas from my Triumph.
Total time spent was about 1 hour after pulling the unit.

 

[JHZR2]

Ive replaced voltage regulators due to bad brushes. Everything else Ive left to a competent rebuild.

 

[Errtt]

I remember back some time i used to get kits for alternators and starters. Don't see em like I used to.

 

[TFB1]

Originally Posted By: expat
Yes, A few times, but I have only replaced brushes and bearings.
It worked out pretty well for me, lasting over 100K miles in one instance.
As far as Diodes go, I'd say 'If it ain't broke, Don't fix it'

Alternators were a Nippondenso from a Toyota 22R and a Lucas from my Triumph.
Total time spent was about 1 hour after pulling the unit.


Bingo that's how I've always done it... On a freshen up it's wear parts only and if it has one, maybe the internal regulator...

 

[rjundi]

I have rarely had alternator failure even with vehicles run to 250k miles.

This includes Honda, VW, Subaru and Jeep. My wife's Subaru ended up with a bad diode? as the voltage was variable. No break down just nutty light show and dash going crazy.

Wait for failure as it likely will not happen.

 

[antonmnster]

I've replaced brushes/regulators, which in Bosch units takes about 5 minutes. I've also popped dust shields off the bearings, greased, and put back together.

Generally they aren't super complicated. I wouldn't be afraid to rip into one.

 

[AandPDan]

I've done it, just the wear items. New brushes and bearings only.

I would do it again.

My philosophy with the electronics, if it ain't broke leave it alone.

Actually, the only REAL problem was that at about 125k, the brushes were worn. The slip rings weren't bad, just a light cleaning was all they needed.

 

[tightwad]

Originally Posted By: mechanicx
Some of the later model alternators are harder to get apart and to get replacement internal parts, but some guys rebuild some of the late model alternators. I use to rebuild the older model alternators. Not as preventive maintenance but if and when they went out. They were much easier to take apart and put back together, and parts were readily available. You could often overhaul one that went out for under $5, usually with just a diode trio. Things use to be designed more for overhauling.

I agree with you that rebuilding the original would be better and cost effective, if not time effective, to those crummy aftermarket rebuilds. Plus les money going to china

. You can sometimes get a higher quality OE reman but that's more money.

I think maybe getting the same alternators out of the junkyard at a good price to practice on, for spare parts, and to have repaired and ready to go unit might be a good way to go about it.


Good information. Get a FSM and research how hard your particular unit is to work on. If you feel comfortable with it, give it a try. Pass on the"overhaul kits" in the bubble pack. Get name-brand bearings and brushes-Standard, Echlin, Borg-Warner, etc. Worth a little more $$ in the long run.

 

[Chris142]

I have done the Older GM ones with the internal regulator. really easy to do those. Just put in new bearings, brushes,Diode Trio and a regulator and your done. Takes about 30 minutes and I always felt that was better than a store bought rebuild. Now I have a shop right next door that rebuilds starters and Alternators plus 2 other places within 10 miles so I don't bother with rebuilding them myself any more.

PS. The older round Chrysler Alternators had external brushes. Usually the Diodes went bad on those before the brushes did.

 

[01rangerxl]

I never really thought about rebuilding an alternator myself. Out of curiosity I decided to see if there was a kit for my truck, and there is...if you live in Mexico. Auto Zone sells an alt rebuild kit for my truck from a brand called "Victory Lap," but there is a note that it is for Mexico stores only and instructions are in Spanish. Won't give me a price or allow it to be shipped to the US.

 

[Texan4Life]

I found a how to online and figured i could do it easy peezy. well the phillips head screws we mega tight, and ended up rounding them out. yeah I was using the correct phillips head #, but the article recommended a special screw driver you hit with a hammer (forget what they are called). So I put it back together and went to autozone and got one with lifetime warranty.

Then I found out later from my dad that there is little independent starter/alternator/generator shop in town. So next time I'm gonna let them do it.