AZ Targa

I am going through a bad streak with alternators, last year I had to replace my alternator in my Targa after the bearing went out, had replaced the alternator with a rebuilt unit due to being 1000 miles from home and on a road trip. However that alternator didn't last and failed 8 months later with a whopping 4k miles on it. The company replaced it, but woohoo like I want another one... Now the alternator just went out on my coupe, and I don't want to end up with another junk alternator so I thought I would rebuild the stock alternator myself, just to pull it out to find out it's a remanufactured unit from Bosch. Looking at the alternator's brushes it looks like it was just replaced before I bought the car; about 15k miles ago.

Is it just a PHX thing? How long do these alternators usually last for?

What do the rest of you do, buy a rebuilt alt, buy a remanufactured one from Bosch or rebuild your own?

John McM

I have had my original starter and alternator rebuilt by a semi retired technician as I reasoned that once the wear points were sorted I had a quality unit that would last a long time.

Rebuilding an alternator has one tricky part, skimming the rings but otherwise it's a couple of inexpensive bearings and a new regulator. What is going wrong with yours?

user 723923490

I had mine rebuilt with good results. Pick your shop carefully and you should be fine.

pp000830

I at one time was a product manager for Bendix branded OE components both new, put on new vehicles in the factory, Service New as purchased in the aftermarket from dealers or warehouse distributors and rebuilt as remanufactured from used units (cores).

Rebuild or replace?
All rebuilds are made from cores, someones failed unit.
A rebuild can be anything from replacing one offending part and the brushes to replacing almost all the internals. I would find out what the rebuilder's process is.
Service new (aftermarket purchased) alternators versus OE as installed at the factory do not go through the same quality process and so service new may not provide any service life advantage over a properly rebuilt one.
Not sure if any service new ones are actually made anymore as it would require newly made castings and other parts that probably have not been put on an OE vehicle and therefore manufactured in quite some time. A reverse engineered component to make Service New components for a part out of production where the original tooling no longer excists may also exhibit fundamental design issues especially with the casting that can make for a shorter service life.

Andy

FGL28

Rebuild.

AZ Targa

From what I could gather the rebuilding process consists of replacing the two bearings and voltage regulator which the brushes are attached to and machining down the slip rings.

I have those parts listed above is there anything else I could/should replace? Thanks for the help/suggestions.

nile13

There was a link recently to a brand new Bosch (not rebuild) for $200. That's the ticket to happiness right there. It was on ebay, so search a bit and you should find it.

BTW, no core, so you can rebuild yours by a reputable local shop and have it as a spare or to sell later on.

stace

some time ago I had a discussion about this with Jeff Gamroth of Rothsport and Steve Weiner. Both have had years of terrible results with Bosch rebuilt alternators. they recommend buying OEM. The price is outrageous but they haven't found a reliable alternative for 993s. if you happen to have a local to you shop, that really knows how to rebuild one it might be worth a shot but....keep in mind the success rate is low....

pp000830

The unit includes a commutator that the brushes ride on and a series of wire wound electromagnets that have at this point 20-year-old insulation on them. I suspect one can polish the commutator contact plates and measure the resistance of the electromagnets to see if they are still in-specification and not shorting to ground.

When taking a dead one apart it may be a good idea to figure out exactly why it failed. If the brushes were worn to the point where they lost contact, polishing the contact points is likely the most important thing. If the voltage regulator blew out meter testing all the coils and connectors is likely needed as it blew out for some reason. If the bearings went bad the offending parts are self-evident.

AZ Targa

This unit is no more that 2-3 years old, and can't have more than 20k miles on it. It still looks like it's a new (remanufactured) unit.

KNS

It sounds like you've had a run of bad luck but there is something to be said for how you drive the car and operate the various electrical loads. I know many people will have a lot of stuff switched on (AC, stereo, headlights at night, etc) before the car is even started. After one starts the car with all those things turned on the alternator is working hard to charge the battery post start. An alternator working under those coditions will have a short life span.

I've got 215,000 miles out of my 2004 BMW alternator and it's still ticking but I think that's due to the fact of the way I drive and use the car.

Tremelune

Yikes, there's really no known list of high-quality rebuilders in the US??

I always hoped for a way to put a standard alternator where the AC compressor goes. A monstrous alternator for a Chevy is like $100.

FGL28

Any competent mechanic can rebuild an alternator.

nile13

I'm sorry... can you please explain what "alternator working hard" means in this case. Do you have a clear understanding of what the alternator does and how?

Tremelune

The battery is a load, much like headlights. When the battery is depleted, it's a higher load than when it's fully charged. When you start a car, the battery loses a lot of juice, so the alternator is always working harder when a car is first started than after it has been driven for a bit and the battery is topped off (all other electrical loads being equal).

An alternator that runs at 50% capacity will last longer than one that runs at 80% capacity. Waiting to turn on electronics after a car is started puts less of a load on the alternator than turning things on immediately. Whether it is a significant or negligible load in terms of the lifecycle of an alternator, I do not know.