Rebuilding b5.5 Passat alternator (how to)

[Mozambiquer]

So, my wife called me the other day and told me that the "alternator workshop" message came up, and the battery light came on. I knew I could expect that, since I've seen that the alternator normally goes out at about 250k miles, and we're at 220k. I had planned to do it as a maintenance item then, but ole Murphy beat me to it.
Anyway, so I get busy ordering the rebuild parts which came in today.
I jerked it out this evening after work and got to work on it, which you'll see in the photos. Of course I hadn't ordered a new rotor, which was what failed this time, so this will be the first post.
I hope this can be helpful for those who want to get their hands dirty and rebuild their own alternator, instead of paying out of the nose for a new one or one of the junk remans from the parts store.

My alternator is the valeo version. I like the Bosch one better, mainly because you can get the rectifier without buying a whole back housing.

First thing is to pull it out. You'll have to remove the fan, since the fan clutch won't let the lower alternator bolt come out all the way.

When you have it out, there are two 7mm head screws that you need to pull out and then the cover will come off.
Under that is the regulator and rectifier, which also have 7mm screws. Do not try to remove the rectifier, it's not servicable.
Remove the three screws for the regulator and pull it off. You will then see the slip ring. Use a multimeter to test between both rings, there should be continuity. I don't recall the number of ohms there should be, but there should be continuity. Mine didn't have any. Then test between the rings and the main body of the rotor. There should be no continuity there. In my case, there was continuity, which showed an internal short in the rotor.
Gently separate the terminals which are wrapped around the stator leads.
Remove the four screws holding the two halves of the alternator together and remove the front pulley. Gently tap the halves apart separate the pieces and see what you have got yourself into. Remove the bearings.
If you needed to replace the slip ring, now is the time to do that. The valeo is really a pain to replace. I've done a few, but a lot of people just replace the rotor. I was going to replace my slip ring, but the rotor is bad, so I'm not needing that. Now it's time to clean, paint, replace bearings, etc, then reassemble in reverse order. You'll need to solder the stator leads to the rectifier which requires a soldering apparatus. I'm thankful I have a resistance soldering setup, which is ideal for this.

Parts list for the 120 amp valeo alternator:
Clutch pulley: 593490
Regulator: 599316
Rotor: 593566
Rear bearing: 6-202
Front bearing: 6-303
Slip ring: 2606286

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[Mozambiquer]

And since I wasn't going to be able to get it finished today, I stuck the alternator from my mk4 golf project on it. Just had to swap the pulleys. I will be rebuilding this one soon, since the slip ring is pretty worn on it. It's the Bosch, so I may do a write up on it too.

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[zzdiesel]

Curious what the parts cost, particularly the rotor. When my Valeo rotor was bad I got a used Bosch and serviced it instead.

 

[Mozambiquer]

Curious what the parts cost, particularly the rotor. When my Valeo rotor was bad I got a used Bosch and serviced it instead.

I was unable to get oem valeo for the rotor, but I got a j&n premium one. It was $72. A bit pricy, but not the worst.

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[oilhammer]

Your time must be pretty low cost. Do you do any carpentry?

 

[Mozambiquer]

Here's the finishing up. I found out that the rotor I ordered, even though my supplier didn't label it as OEM, that's what it was. So now it's back to oem valeo. Now I just gotta put it back in the car

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[Mozambiquer]

Your time must be pretty low cost. Do you do any carpentry?

It doesn't take me very long to build an alternator. What takes the longest is letting the paint dry lol.
I used to do carpentry and still do it for myself.
In total, my cost was about $120 for a basically OEM alternator. Add in an hour of my time, which if I were billing to a customer, would be $50 then I have a $170 alternator and then I have the peace of mind knowing it's done right, unlike an oreilly's reman.

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[Tom in PT]

Thank you for the post and pictures.

In 42 years of car ownership and about 600,000 miles of driving various makes (Ford, VW, Honda, Lexus) I have never had an alternator problem. But if and when I do, I will also rebuild what I have (or perhaps have the excellent local automotive electrical shop do it), as you have. You know what you are getting and can do it right. I had this local shop rebuild a large, 50 year old, powerful electric motor for a marine application and it is as good as new and the rebuild was very inexpensive.

 

[oilhammer]

It doesn't take me very long to build an alternator. What takes the longest is letting the paint dry lol.
I used to do carpentry and still do it for myself.
In total, my cost was about $120 for a basically OEM alternator. Add in an hour of my time, which if I were billing to a customer, would be $50 then I have a $170 alternator and then I have the peace of mind knowing it's done right, unlike an oreilly's reman.

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I think that was more than an hour. Especially since you had to do two R&Rs

When my Valeo died at 160k, a Bosch was installed. Which cost me all of $260 and only one R&R. You work cheap, if you are interested in redoing the back of my house and framing out a deck let me know!