new vs rebuilt alternator...cost & quality

quinnski · Sep 11, 2010

Greeting, this is my Maiden Voyage - ist posting. I want to know what the cost would be and which is a better choice for an alternator for 2003 530i. How much is a new one vs a rebuilt one?

Also, they told me that the Alternator could not be rebuilt. Should I get it back from them?
I have a feeling they will keep the old one and rebuild it to be sold later and in the meantime they will sell me another...The old "Razzle Dazzle". What ever happened to honesty?

Info would be appreciated as I will return to the mechanic on Monday. If it is a new Bosch as opposed to a rebuilt one, how can I verify that the part is indeed, new?

thanks,
Q

cn90 · Sep 11, 2010

Rebuild yourself. I posted a DIY in the forum, search for it.
Should not cost more than $60, your own labor.

If you need a 2nd opinion, my cousin has a BMW shop in Gardena CA:
18020 S. Vermont
Gardena, CA 90248
310-532-3145.

bluebee · Sep 12, 2010

cn90 said:
Rebuild yourself.

From the bestlinks thread ...
- cn90 alternator rebuild DIY

bluebee · Sep 12, 2010

quinnski said:
which is a better choice for an alternator for 2003 530i. How much is a new one vs a rebuilt one?

I just went through the same thought process for a 2002 525i.

The price of a new Bosch 120 alternator would have been astronomical; so, there was no question that I was going to buy a rebuilt alternator. I didn't have time to rebuild it myself because it's my only vehicle; but, in hindsight, I wish I had stockpiled the components from cn90's DIY.

I got my rebuilt Bosch 120 from OEMBimmerparts for less than $200 (details here) overnight.

quinnski said:
they told me that the alternator could not be rebuilt. Should I get it back from them?

It's my understanding that most states make it law that you get your part back if you ask for them PRIOR to them working on the car. Of course, they'll still have the parts if you ask soon enough after they start work - but the point is, if you ask right, they have to give you the old parts, by law.

I'm not sure how that applies to items that have 'core charges' ... these core charges always confused me anyway. I paid a core charge of $100 for my alternator, which cost $25 to ship back, so, the core charge, in essence, cost me $25 in real dollars.

quinnski said:
I have a feeling they will keep the old one and rebuild it to be sold later

As I said, I don't know how "core charges" work, especially to a mechanic.
It's my guess they too will have a core charge (although I don't know this for a fact), so, they'll send the alternator back to the remanufacturer. It's my guess that the final say on whether or not it can be rebuilt will be by that remanufacturer ... but by then, it's way out of your control (or concern).

quinnski said:
What ever happened to honesty?

I've been cheated & treated well when I went to an indy; I've only been cheated when I went to the stealer ... but I've never been cheated in a bimmerfest DIY!

My suggestion if you have the time is ...
a) Get your car and old alternator back
b) Order a rebuilt alternator from OemBimmerparts
c) Replace it yourself (here instructions I wrote up with cn90 help)

quinnski said:
If it is a new Bosch as opposed to a rebuilt one, how can I verify that the part is indeed, new?

Dunno. My rebuilt alternator (see pic below) came with stickers on it saying it was rebuilt and by whom.

quinnski · Sep 15, 2010

Thank you very much for your reply. I appreciate the time you took and the information you supplied. My new mechanic turned out to be fair and honest, hard to believe in this day and age where greed is the motivating factor. The mechanic and you have restored, a portion, of my faith in humanity.
-JQ

quinnski · Sep 15, 2010

ATTN: BLUEBEE
Thank you very much for your reply. I appreciate the time you took and the information you supplied. My new mechanic turned out to be fair and honest, hard to believe in this day and age where greed is the motivating factor. The mechanic and you have restored, a portion, of my faith in humanity.
-JQ

cn90 · Sep 15, 2010

Bluebee,

The concept behind core charge is simple.

Let's say an Alternator costs $200 with "core charge" of $100.

So you get the Alternator provided you return the old Alternator so they can rebuild it and re-sell it later, making money.

Let's say you fail to return the old Alternator, the seller will charge you $100 on your VISA Card for failure to return the core, now your cost is $300 for failing to return the core.

However, if you return the core as instructed, then it would cost you $25 for the shipping; so your total cost to get a rebuilt Alternator is $225.

bluebee · Sep 15, 2010

cn90 said:
The concept behind core charge is simple.

The part I was unfamiliar with was when an Indy does the job.

Does the Indy pay the core charge and then give it back to you in the price?

Or, does the Indy pay the core charge and then NOT give it back to you in price?

Or do the suppliers not charge the Indys the core charge and you just pay full price?

manticore33 · Sep 15, 2010

Napa in my area sells remanufactured Bosch 120 amp alternators for $194 + $35 core charge, 90 amp is $149 + core (not sure why you would go mail order when local is the same price).

So for $35 you could keep and rebuild it, but with a lifetime warranty on the remanufactured unit, why would you need to?

And my two nearby Napa's had the alternator on the self too.

bluebee · Sep 15, 2010

manticore33 said:
not sure why you would go mail order when local is the same price

When I needed an alternator pronto, I went to Napa in San Jose, AutoZone, and Kragen.

None had the Bosch 120 in stock. Some could get it. But it wasn't the same price as mailorder from our sponsors.

BTW, add at least $25 to the price for an alternator to ship it back to the sponsor (ask me how I know) so if the core charge is, say $35, you only get $10 net back from that core charge.

cn90 · Sep 15, 2010

Nothing wrong with NAPA alternator. Infact, I called a few rebuilders in the US to get the detail (these rebuilders rebuild the Alternator and ship them to Pepboys, NAPA etc. etc.).

A proper rebuilding process involved. The issues for each item are in italicized letter:

1. New front bearing
- Some places put in new bearing but in 99% of the time, you get Chinese bearing instead of brand name like Koyo, SKF, F.A.G.
- Some check it, if no play, then they simple re-grease it and re-use it: not recommended.

2. New rear bearing
- Some places put in new bearing but in 99% of the time, you get Chinese bearing instead of brand name like Koyo, SKF, F.A.G.
- Some check it, if no play, then they simple re-grease it and re-use it: not recommended.

3. New brushes
- This is a must because at 140-150K when the alternator fails, the brushes are worn down.
So virtually all rebuilders install new brushes.

4. New Voltage Regulator (a.k.a = "Rectifier")
- Here is the kicker: if checked OK, most simply re-use it but read on.... Although this is a solid-state device (no moving part), it is rated at let's say 2 million cycles of alternator revolutions, then the solid state device just fails any time after that.
- The reason most rebuilders re-use the Voltage Regulator is cost (a good Voltage Regulator costs some $50-60/each).
- This is also the reason why many people run to Autozone, get a rebuilt Bosch Alternator, only to find out 1 month later the Voltage Regulator failed! Some in this forum have gone through 3 Alternators in a 6-month span. What a waste of time and effort!!!

So unless you know exactly how a rebuilt Alternator was performed, rebuild the Alternator yourself for $60.

Sadly, the day of good craftsmanship and quality work is over, many people simply go for a quick buck, but you the owners pay for this poor practice.

bluebee · Sep 15, 2010

cn90 said:
So unless you know exactly how a rebuilt Alternator was performed, rebuild the Alternator yourself for $60

This is scary. If only I had stocked the parts, ahead of time.

My rebuilt alternator was bought from a sponsor.

At least for the sponsors, we should know what parts are put in, right?

Do we know that information for the sponsors who sell alternators?

supradupe · Sep 16, 2010

cn90 said:
4. New Voltage Regulator (a.k.a = "Rectifier")
- Here is the kicker: if checked OK, most simply re-use it but read on.... Although this is a solid-state device (no moving part), it is rated at let's say 2 million cycles of alternator revolutions, then the solid state device just fails any time after that.
- The reason most rebuilders re-use the Voltage Regulator is cost (a good Voltage Regulator costs some $50-60/each).
- This is also the reason why many people run to Autozone, get a rebuilt Bosch Alternator, only to find out 1 month later the Voltage Regulator failed! Some in this forum have gone through 3 Alternators in a 6-month span. What a waste of time and effort!!!

So unless you know exactly how a rebuilt Alternator was performed, rebuild the Alternator yourself for $60.

the voltage regulator and rectifiers are two separate things. the voltage regulator has the carbon brushes and costs 50-60 like you said. The rectifiers on the other hand, is very difficult to source. I was not able to find suitable rectifiers for my bosch alternator and there is a lot of heavy soldering and desoldering to do if one wants to replace the rectifiers. I had rebulit mine only to find out 6 months later that the rectifiers are dead. So, going with your logic, rebuilding yourself can also be a waste of time and effort. At least if one buys a remannufactured alternator, one can get limited life time warranty and get it replaced. Rebuilding on your own, those parts are warranted only for 1 year at most and you are still stuck with a POS.

TemporarySanity · Sep 15, 2010

I can't speak for alternators on "lesser" cars"

but as for the 540 liquid cooled one, I have not had any luck with remanufactured ones. I have a few friends that haven't any luck either so now when we have alternator issues, we just buy new. Not cheap but much less trouble in the end.

manticore33 · Sep 15, 2010

Sorry to hear that bluebee (I thought about doing CN90s rebuild, but I needed the car ASAP). Being in Central Ohio I am lucky with quick shipping from the any of the coasts (UPS/Fedex have distribution facilities here) and major part-chain warehouses are nearby. There is also Napa warehouse about 15 miles from my home and literally the Delaware Distribution Center for Advance Auto Parts and Jeg's are in my back yard (not that I shop at Jeg's). For local Napa or Advance Auto Parts stuff, I can get it same day warehouse pulls duing normal business hours. Oh, and I am friends with both of the Delaware location's of Advance Auto Part store's managers so special pulls and price matching are not a problem.

Online stuff is 3-5 days max.

Indy's pay the core charge and get the core charge refunded when they return the part. The actual cost of the part they charge is likely list. Go into an auto parts store and you will see a two costs. The list price is typically what the shop charges the consumer after performing the repair. So, when you are using a shop they make their margins on the list price of parts and book time. A lot of part stores will deliver the parts to the mechanic and pick any returns and cores and have less than retail discounts too. For instance AAP might sell brake pads to a shop for $13, charge a consumer $30, and list might be $45. If you look at the mechanics invoice for the service work the person having the work done would be charged $45 for pads, 1.5 hours book time (even if only took 40 minutes to do), then other materials.

540 M-Sport · Sep 16, 2010

As CN90 states, there is a wide variance in the quality of rebuilt electrical parts. I have only had good luck when I purchased rebuilt electrical parts either from the dealer (BMW/Honda/Nissan) or from an online retailer that sells products rebuilt by the oem manunfacturer (or their designated contractor), example: Bosch rebuilt alternator, or Nippondenso rebuilt starter.

Rebuilt stuff from chain storres, and independants can really vary in quality, depending on who is doing the work. Typically the chain store stuff is the worst, as they are driven by a national contract, and price is king, so they only replace what is absolutely necessary, then clean it up and paint it, put it in a box and say "lifetime warranty".

I got my rebuilt alternator for my 540 from BMW Seattle, they installed it too (emergency repair) and it was super expensive, but comes with a "lifetime warranty" that is honored at any BMW dealer in North America, parts and labor. So I basically paid $300 extra over the online price for the lifetime warranty versus the two year warranty that Bosch offers (it is the same exact Bosch factory rebuild). My understanding is if you buy the alternator from BMW "over the counter" and dont have them install it, their standard 24 month unlimited mileage warranty applies (parts and labor), not the lifetime warranty.

I have about 80k on that alternator, and hope to keep the car long enough to get my $300 back out of BMW!

cn90 · Sep 16, 2010

My bad,

Voltage Regulator and Rectifier are 2 different entities (I took College Physics too long ago...

).
In some other alternators, these 2 items are packaged together.
In this particular Bosch Alternator for BMW E39, they are located separately.

Talking about component failure, I think the Voltage Regulator fails more often than the Rectifier part.

Attached is an updated diagram:

bluebee · Sep 16, 2010

oooooh. Nice. Thanks cn90.

FWIW ... I took college physics years ago too!

So, for newbies ... from memory of college courses ...

Voltage regulator ... regulates the voltage (presumably to ~14 1/2 volts or whatever it's set at).

Rectifier... changes the AC to DC (generally with diodes in a full-wave configuration, maybe wheatstone bridge).

16valex · Sep 16, 2010

bluebee said:
oooooh. Nice. Thanks cn90.

FWIW ... I took college physics years ago too!

So, for newbies ... from memory of college courses ...

Voltage regulator ... regulates the voltage (presumably to ~14 1/2 volts or whatever it's set at).

Rectifier... changes the DC to AC (generally with diodes in a full-wave configuration, maybe wheatstone bridge).

Bluebee, You mean rectifier converts AC to DC right!

16valex · Sep 17, 2010

Good job Bluebee, Now explain to us how did they do to stretch that Wheatstone bridge DC output to a constant DC output.

bluebee · Sep 17, 2010

16valex said:
Now explain to us how did they do to stretch that Wheatstone bridge DC output to a constant DC output.

Again from memory, the easiest way is to store the charge (which can be done with transistors acting as capacitor multipliers) so they bleed off charge to fill the valleys and end up with a smoother voltage curve.

540iman · Sep 19, 2010

Come on BB, you aren't posting from memory!!! Good job of explaining how the diode acts and essentially why the tests we do on the speed sensors works. I can't tell you how many times I have used a string of rectifiers to reduce voltage (poor man's voltage regulator). Say you had a 9V wall wort and needed instead a 6V wall wort (bad example as wall worts have terrible regulation). So, you need a 3V drop. 4 diodes in series will reduce voltage 2.8V which is close so you could add 4 diodes in series to the positive side of the wall wort and as long as the diodes are rated for at least the current you will draw, they will drop the voltage beautifully. Some might try a resistor, but the voltage drop will then become a function of the current draw so a given resistor will drop voltage a different amount depending on the current draw (E=I*R) so 2.8 volt drop requires knowledge of whatever the load will be to determine what resistance is needed. Ok Blue, can you explain why when you use a full wave bridge rectifier that it will not drop the input AC voltage, but increase it by a factor of 1.414?? In other words, if you have 10 volts AC and want to turn it into a full wave DC voltage using a bridge rectifier, that the voltage at the output side of the bridge will be 14.14V?? Just testing you!! If you instead use a half-wave set-up, the output will be REDUCED by a factor of .7 or about 7V DC will be produced instead of 14VDC if you use a Full wave bridge. Splain that will ya Blue??!!

My question is: Has anyone found an alternator re-builder who states the ALWAYS replace the regulator and rectifier trio? I have only found, as most have, the guys who say "replaced if necessary" which means if it is turned in as a core with a rectifier trio that is working at that minute, they leave it! It could fail from use/age in 5 minutes! At least if they were to replace you would know you are starting with a motor that has *zero* miles on it. If anyone finds a site that says they always replace the semi-conductors regardless, I would love to know who does this.

bluebee · Sep 19, 2010

540iman said:
Come on BB, you aren't posting from memory!!!

Actually, I was. I used to use the 7805 all the time when I took an electronics class in adult school. I never could understand the 7905 which was a negative voltage regulator. (Still don't understand it to this day.)

Ok Blue, can you explain why when you use a full wave bridge rectifier that it will not drop the input AC voltage, but increase it by a factor of 1.414??

Seriously I'm not looking this up. But I do remember "something" somewhere, about 1.414 being the RMS voltage. Am I at least in the right direction?

My question is: Has anyone found an alternator re-builder who states the ALWAYS replace the regulator and rectifier trio?

Actually, it would be nice to get a bill of sale that explains which components were replaced with what (which is cn90's whole point). I bought mine from OEMBimmerfest's web site but I wouldn't know what was replaced.

If anyone finds a site that says they always replace the semi-conductors regardless, I would love to know who does this.

+1.414

ketchup · Sep 19, 2010

good god does she(?)know her stuff!

cn90 · Sep 20, 2010

From the pro rebuilder:

- When a voltage regulator goes bad, it can damage the diode trio (rectifier). But as a general rule, voltage regulator fails frequently with age.
The rectifier rarely rarely goes bad.

- A major rebuilder for Bosch in Michigan can offer:
a. New Bosch Alternator (no need for core charge because it is new): $400
b. Reman Bosch Alternator: $180 (with core charge) and who knows what parts were replaced.

Some more tids/bits:

1. To look up PNs for Alternator, this is a good website from the UK:
http://woodauto.com
My 1998 528i Rectifier is "RTF39818" or Bosch PN 1127319712.
http://woodauto.com/Component.aspx?Ref=RTF39818

2. A good supplier for rebuilders and individuals is IAT USA Inc.:
http://www.iat-usa.com/
IAT USA Inc.
61-32 2nd Avenue
Woodside, NY 11377 USA
Tel : (718) 956-4248 Toll Free: (800) 872-8890
Fax: (718) 956-4310
Email: sales@iat-usa.com

anbu_nee · Oct 11, 2010

new alternator for $550

I just replaced my alternator for $550 and $120 labor. I didn't know rebuilding in an option.

cn90 · Oct 11, 2010

anbu_nee said:
I just replaced my alternator for $550 and $120 labor. I didn't know rebuilding in an option.

When did yours fail? 125K, 150K, or 175K miles?

wolfen · Oct 11, 2010

$400.00 for a new alternator is a good deal considering. At that price as of now, i wouldn't bother with a rebuild. The car needs what it needs and should get new OEM parts. I learned back in the day that saving money on rebuilt Starters, alternators etc is wasted money. You will in fact buy twice or trice.

cn90 · Oct 11, 2010

I disagree,
- Rebuilt alternator and Bosch from reputable rebuilders is as good as new.
- Rebuilding these things YOURSELF is even better if you know what you are doing.

bluebee · Oct 11, 2010

Plus, if you rebuilt it, you're more likely to have ALSO replaced the belts, mechanical tensioners (or hydraulic tensioner pulleys), and idler roller.

The only problem I see with rebuilding is you need to plan ahead!

It would be nice if a single rebuild "kit" were available for the Bosch 120 and whatever other common alternator is used in the E39.

bluebee · May 29, 2014

For the crosslinked record, there is a nice valeo rebuild going on today over here:
> E39 (1997 - 2003) > No power from alternator + no red light battery

LaroxMW said:
This are pictures with alternator dissambled. It is little oily because i clean with gas
The car is E39 2001 2.2 bezine, 170 horse, M54 motor.

See also:
- Complete DIY for how to test a BMW battery & alternator (1) & how to determine exactly what alternator you have (1) & how to determine the proper replacement alternator brand and amperage [Valeo, Bosch, 90A, 120Amps, or 140 amps] (1) & how to tell from the part number if a replacement alternator is actually rebuilt "by" Bosch (1) & one users' example of total electrical failure (AAA towed away) alternator repair (1) [Read post #66 & post #107 & especially post #146] & a DIY for replacing the E39 I6 alternator (1) (2) (3) (4) (5) or E39 V8 alternator (1) (2) (3) (4) & why you want to clean out the air-cooled alternator air duct & cooling vents (1) (2) (1) (2) & does an ATF leak from power steering hoses onto the alternator cause the bearings to fail (1) & why rebuilding an alternator is preferable to replacing (1) & cn90 DIYs for rebuilding a 1998 air-cooled BMW Bosch alternator (1) (2) or his VW Bosch alternator (1) & cdawg246's quest for materials for a Bosch water cooled alternator rebuild (1) & Aioros' 1999 Valeo Alternator rebuild DIY (1) and his quest for materials (1) & Cn90's explanation of where to get hard-to-get alternator rebuild parts (1) & a DIY for replacing the brushes in an (Audi) Valeo alternator (1) & a Bosch alternator bearing replacement from a 1997 MB S600 (1) & from a Range Rover (1) &, if it's not the alternator, a diagnostic procedure to test for overnight parasitic battery drain (1) & how to find all the fuses (1) & how to choose a good aftermarket battery (1) and a simple battery replacement DIY (1) & where to find the battery explosive charge emergency quick disconnect (1) (2)

bluebee · Apr 30, 2015

Useful information today...
> E39 (1997 - 2003) > Emergency help needed

cn90 said:
Google Bosch AL0703N (bosch AL0703X is the rebuilt version, it is hit-and-miss).
For $229, you will have a brand new alternator that should last the remaining life of the car.

PS: Rebuilding alternator is fine too but:
- VR is $60
- Two (2) bearings are about $60
So, if you don't want to rebuild then go for new, not rebuilt.

new vs rebuilt alternator...cost & quality

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