DIY: $5 Alternator Fix - replacing brushes (Valeo)

[walky_talky20]

The most common failure of the Valeo-manufactured Audi alternators is simply the brushes. Replacing these brushes is not very difficult. It is also very inexpensive, especially compared to buying a new alternator, or a sketchy parts-store (chinese) "rebuild". The brushes will usually last until at least 100k miles, and will generally fail somewhere between 120-180k. At the shop I work at, we usually replace or at least inspect the brushes during the timing belt service to prevent the failure.

A couple things to note:
- Standard DIY disclaimer applies. Info purposes only. Use at your own risk. I'm not responsible if you hurt yourself or your car.
- There are 2 brands of alternators Audi uses. Bosch and Valeo. This guide is for brush replacement on Valeo alternators. Perhaps a forthcoming addendum may cover the Bosch units.
- Not just for B5's. This repair will work for many modern Audi and VW models with Valeo alternators: B5, B6, C5, MKIV, etc
- This service is best done as preventative maintenance. If the brushes are permitted to fail, it can cause strain on the other alternator components as the charge circuit falls off and returns intermittently. That said, if the unit is dead anyway, it is probalby worth $5 to try this fix first.
- This repair is to fix or prevent a "no charge" or intermittent charge situation. If you're having other troubles, this fix may not help you.
- 1.8T owners CAN replace the regulator without removing the alternator. See post #17 (thanks to flashburn).
- Procedure is the same for 90A and 120A Valeo's. In fact, the regulator/brush pack is interchangeable.

Parts:
- The replacement brushes I use are Standard (brand) JX94 brushes. These are usually around $5 for the set. This particular part number is listed for the early 80's Toyota trucks. Not a direct fit, but require minor filing.
- The entire voltage regulator/brush pack is available aftermarket. Details at the end.

Remove the alternator. This differs greatly depending on chassis/engine. By "differs greatly" I mean it's super easy on an A4 1.8T and a pain in the butt on a B5 S4 2.7T. Make sure you disconnect the battery first. Here is a pic of the only tricky part on the B5 1.8T, removing the cooling fan. I also recommend removing the top intercooler/TB hose as it gives you more room, but it isn't absolutely necessary.



Alternator removed


See Valeo markings


Back cover off. Two 7mm bolts


Remove regulator/brush pack. 3 7mm bolts.


See very little brush material remaining


Especially if you are repairing a non-working unit, now is a good time to check for other failures. With a multimeter, testing across the 2 rotor contacts should give continuity with low-resistance. I measured about 3-5 Ohms. I have seen a rotor failure before. The contacts had no continuity (open circuit, O.L.). In that case, I had to source a used replacement (further disassembly is much more difficult). You should also check that neither contact is shorted to the case (should be open circuit). You may also want to verify that the bearings are good, etc. The diode pack is another item you can test, but it requires desoldering some very high-temp solder (it must be disconnected to test it). I've yet to see a diode pack failure on an Audi/Valeo unit, but it is certainly possible.


Back to the brushes. Remove the goop from the contact. Just pick it off.




Remove the black cover from the regulator. You should be careful from here on, as the beige colored plastic is somewhat brittle.


Next we will be de-soldering the contacts at the back. Use your own favorite method for this. I used a soldering iron and blow-gun liquify then blast off the solder (watch your eyes!). Once most of the solder is off the joint, I used small metal pick/screwdriver to slightly open up the metal "tube" the wire is soldered in. Then I added some more heat, and the spring tension pulled the wire out for me.







Repeat on the other side.

Here are the new brushes


They are not a direct fit, but after some quick work with a file, they are perfect. Compare with the original brushes for a size target You can also test fit as you go by sliding the brush into it's slot until it fits. Not snugly, it has to slide easily. But no too loose either.


Put the spring over the wire and push it into the slot. Hopefully the wire will come through the hole at the back for you. It may take a couple tries and some creativity.




Once the wire is out the back, you adjust the wire length for the maximum "out" position. You want it as far out as possible without being too loose. Once you choose the length you can crimp the metal tube slightly with some pliers to hold the wire position.




Then solder away.


After it's cooled a bit, clip the excess wire and apply a glob of RTV silicone, just like the factory did.


Reinstall the regulator/brush pack. This takes slightly more finesse, as the brushes are longer now, and will need pushed in against their springs. Bolt it down and push on the black cap. It should click.


Slap on the cover and install your rebuilt alternator!

If the filing and soldering looks a bit daunting, or if your problem is not the brushes but the voltage regulator, fear not. The voltage regulator/brush pack assembly is available. This one is from Transpo, part M521. Price is around $30. The replacement regulator comes with this nifty blue tool. It helps with installation of the new regulator by holding back the brushes for you.

[f15046]

Excellent writeup, thank you for taking the time to post this.

[biketsai]

Sweet! Awesome write-up

[ECS Tuning-Audi]

Awesome write up indeed. I've been down this road before though unsuccessfully. I had waited too long to replace the brushes and the contacts on the spindle (forgetting the technical name) were worn through and new brushes weren't enough to save her :(

[oneohone]

Nice write-up! I wish I knew this when my alternator failed!

[ADNpro]

This is definitely a nice write up and a money saver for sure!

[somebody5788]

Now you need to add replacing the bushings to the list too! almost a completely rebuilt at that point lol

[99blueb5]

this should be added to DIY list mods

[somebody5788]

this should be added to DIY list mods

Nothing ever gets moved there.... I have to DIY's I made that I think are pretty well done and they were never moved.

[blacka4]

Nothing ever gets moved there.... I have to DIY's I made that I think are pretty well done and they were never moved.

Well maybe I can help with that

[coolgraymemo]

nice write-up

[kaban]

wish i saw this last week when my valeo took a dump. a refurb unit was $165 but I would have preferred to do this.

[flashburn]

Do you have to put the car in service position to get to the alternator?

[flashburn]

Also, where do I find this darned rebuild kit!?!? No chain store has it?

[walky_talky20]

Service position is not necessary on a 1.8T.

Which kit are you referring to? The brushes are widely available, Standard JX94. A good parts store would probably be able to order those. A good alternator parts place would be able to sell you the exact brushes, with no modification needed.

http://www.amazon.com/Standard-Motor...5298179&sr=8-1

The regulator/brushpack assembly is harder to get. You probably need to get in touch with an alternator rebuild shop or similar to get it. But I did find one a few on ebay:

http://cgi.ebay.com/ebaymotors/ws/eB...d=370113057887

http://cgi.ebay.com/ebaymotors/ws/eB...d=350395976492

For help in searching, the original Valeo part number for the regulator assembly is 593941.

In My Opinion: Anything more than replacing the brushes in these alternators is not really worth it. A working junkyard 120A Valeo can be had for as little as $35, which is less than buying the regulator. So that is my suggestion. If you find the regulator/diode pack/rotor to be faulty, buy a good used alternator, throw some new brushes in it and enjoy.

[flashburn]

Thanks for the tips. Tackling this right now.

[flashburn]

Alright. On the 1.8t you can totally, and very easily, replace the brushes and voltage regulator assembly without removing the alternator.

Start off with removing the upper intercooler hose - 2 x flat head screw driver

Simply remove the sensor wire - plug on socket

Then the positive cable 1 x 14mm

Then remove the plastic cover on rear of alternator - 2 x 7mm



Then remove the voltage regulator - 3 x 7mm

And reassemble with your new voltage regulator as the brushes are self contained in the regulator. I got mine from Charles Electric in Akron on Grant St. 60 bucks - 330-535-6269. They are a GREAT company to work with, local mom and pop style and have affordable rebuild prices. They don't normally do parts but have GREAT rebuild prices on Bosch and Valeo Alternators - 180ish. Autozone wants 165 for a Chinese knock off so the extra 25 is worth it to me!!

[Baseballer]

I was thinking of pulling an alternator from a junkyard, but I was worried about the prospect of buying one that's just about to go out. Is it the OP's opinion that you pull a used one and hope for the best, or check the brushes first?

[walky_talky20]

I was thinking of pulling an alternator from a junkyard, but I was worried about the prospect of buying one that's just about to go out. Is it the OP's opinion that you pull a used one and hope for the best, or check the brushes first?

Yes, pulling a junkyard one isn't a bad idea. That is what I did, actually. My alternator failed (I was waiting to refresh the brushes when I did the t-belt, but the failure came sooner). The brushes were worn, but actually the rotor was open-circuit. So I got a used one from an import yard for $35. I replaced the brushes before I installed it (this is the unit that is shown in the DIY) and it was good to go. Originally my car had a 120A Valeo, but I ended up with a 90A version (despite asking specifically for a 120A, but it doesn't really matter). It's been working great.

[Outlawjones]

Seriously walky_talky20 they should just give you your own section on here! I mean you go into such detail when answering questions or DIY projects. Hats off to you man!

[walky_talky20]

Seriously walky_talky20 they should just give you your own section on here! I mean you go into such detail when answering questions or DIY projects. Hats off to you man!

Thanks. I hope my input is helpful, or at least insightful to some. I very much enjoy it.

[somebody5788]

I got the brushes. I really need to get around to installing them..... FYI I got mine from NAPA by crossing the number. Wholesale price was a 1.50 or something haha.

[walky_talky20]

I got the brushes. I really need to get around to installing them..... FYI I got mine from NAPA by crossing the number. Wholesale price was a 1.50 or something haha.

That's great. If you have any part numbers, please share them here if you can. Good Luck.

[somebody5788]

That's great. If you have any part numbers, please share them here if you can. Good Luck.

I'll have to remember to look it up. Just calling NAPA with the number you provided and ask them to interchange it they can tell you then though.

[juttin3]

i got a question . sorry to bring up old thread. i had a 120 valeo that broke in my b5 1.8 and i replaced with a 90a that only had 2 screws on back for skinny blue and thick black wire. so i cut off the connector i had on the blue wire. this was several years ago , recently i bought a remanufactured 120 volt valeo that was same as what i had but it had the clip on it for the blue wire , and the alternator has 2 pins in the clip. i dont have the original clip any more . do both of the pins inside alternator connector need to be connected to the solid blue wire ? or does just one of the pins get connected. i only see one solid blue wire along with the black one. i had to get rid of the 90a because the car would have to be revved high after starting or battery would stay low .

[walky_talky20]

I do believe there are 2 contacts for the electrical connector to the voltage regulator. One is for the field voltage and the other would be for the charge light on the dash, which is not used on a B5 (cluster does all the magic for that). So, to answer your question: the one small wire should connect to just one of those 2 pins, not both, as far as I know.

My 90A unit has been working great. I think the voltage falls off slightly more at idle compared to the 120A version, but that is only if I have lots of accessories on (defroster, seat heaters, headlamps, etc).

[juttin3]

Ok thank you. I didn't mention that this is the 2nd 120 alt I just got. The one I put in 3 weeks ago broke within 2 weeks. I connected that wire to both pins. Wasn't sure if that's what broke it. So before I put this replacement in I wanted to make sure. I saw on elsa wire diagrams that it looks like it connects to pin 1. So I'm gonna try that. This is a 99.5 tiptronic fwd.

I do believe there are 2 contacts for the electrical connector to the voltage regulator. One is for the field voltage and the other would be for the charge light on the dash, which is not used on a B5 (cluster does all the magic for that). So, to answer your question: the one small wire should connect to just one of those 2 pins, not both, as far as I know.

My 90A unit has been working great. I think the voltage falls off slightly more at idle compared to the 120A version, but that is only if I have lots of accessories on (defroster, seat heaters, headlamps, etc).

[a4rings]

how can you tell how many amps a valeo alternator is?

[walky_talky20]

They are marked on the case. I think it is a sticker, though.

[a4rings]

do you have any idea where on the case? do you mean the black part on the back that comes off with the 2 x 7mm ?

[walky_talky20]

Nope, it is on the sticker with the part numbers and such:

[a4rings]

If my car came equipped with a Valeo alternator can I replace it with a bosch unit? also do you guys have any advice to where i can find a replacement Valeo 120 volt unit? all of the ones i found at junkyards had a much different pulley attached to the alternator

[a4rings]

All the ones i find online and in the junkyards has a larger pulley that is attached with a bolt/nut while mine is a bit smaller and pressed on?

[a4rings]

Hey guys so i took a picture of the alternator that i took off my 2000 a4 1.8t and i'm trying to find out if this alternator i found on ebay works because my pulley is pressed on and all of the junkyard ones i find all have larger puleys and they are bolted on.








NOW THIS one below IS THE EBAY ONE. Can i replace my old one with this unit? Is the pulley the same?

http://cgi.ebay.com/98-99-00-01-02-A...item19c75d6c84




The only difference in terms of #'s is

Mine: 2542232A
Ebay: 2542232B

[walky_talky20]

Looks like the Audi part number is a match anyway. I don't see why it wouldn't work. There was a change in pulleys over to a "one-way clutch" type pulley at some point, but they are cross-compatible. The clutch ones do have a failure mode where the pulley falls apart. I've seen it more on the Jetta's though. Both the stationary and clutch-type pulleys will unbolt, but the clutch ones require a $50 tool to take unbolt them.

Both of those pulleys look the same to me, unless I'm missing something obvious.

[a4rings]

The main thing i am worried about is the pulley being a different size than my original one. All of the ones, literally a donzen, that i found at the junkyards all had larger pulleys than mine. Would i just be able to adjust the tensioner appropriately to use a alternator with a slightly larger or smaller pulley than what came equipped on my car?

[walky_talky20]

If anything, you could just order a slightly longer belt. But I bet it would work just fine.

I'm wondering if perhaps your car has the wrong pulley and all the rest are correct?

I'm off to ETKA to learn about alternator pulley diameters...

[speedydragon]

Remove the black cover from the regulator. You should be careful from here on, as the beige colored plastic is somewhat brittle.

thanks for the awesome write up! But how did you manage to slide that black piece off? thanks!