superdylan

This is how I pulled off the large bearing from the shaft:

superdylan

So, if you're removing the large bearing my way, the large bearing along with a small metal spacer and the bearing plate have been pulled off the shaft. You can remove the 4 screws holding the bearing plate and pop out the large bearing from inside the alternator housing.

Since most of you Porsche-heads are clean freaks, you may want to clean up the alternator housing that you just removed.

superdylan

Now grab the other side of the alternator housing, you know the one with the diodes and windings and circuit board still attached. You can check the diodes here or you can remove the 6 phillips head screws to separate the circuit board from the alternator housing and have a closer look.

superdylan

In case you are curious, here's what it looks like behind the circuit board. I've also shown the plastic retainer ring that sits inside the housing. Note that the retainer ring has a slot to align it into the housing center.

superdylan

Here is the other side of the circuit board...Not really much to see. I tested the diodes and they all checked out fine, but I forgot to write down which side was positive and which was negative. If anyone knows offhand, I can label my picture for it. Note that there are 4 positive diodes and 4 negative diodes.

superdylan

Since my diodes tested good, I decided not to replace them. But, I did decide to replace the slip ring.

superdylan

You must unsolder these two wires before you remove the slip ring!

My 15W solder gun was no match for this. So, I went out and bought a 60W gun that did the job. I used 60/40 solder if anyone cares.

superdylan

After unsoldering the wires, I removed the slip ring with the puller. You may not need a puller, but I used one since it was laying around...

superdylan

Here's a picture of the old slip ring and new slip ring side by side.

If you've got a basic amount of soldering skill, you can remove and install a new slip ring. I used 60/40 solder, a 60W soldering iron with a medium sized flat tip, solder flux, and copper braid. That's it.

superdylan

Now, you can put everything back together the way it came apart.

I got parts to rebuild my alternator from Wagner Alternators. I typed in my alternator part # on their website and a bill of materials spit out.

Here's what I replaced:

WAGNER# DESCRIPTION
W02X-01 6201 2RS BEARING - 12X32X10mm
W02X-45 6304EHSR BEARING - 17X52X17mm
W110-04 CAP
W110-21 BO PLASTIC BEARING RETAINER
W160-01 BO SLIP RING - 28mm
W04X-28 BOSCH DIODE - NEG 35A 200V RIM
W04X-29 BOSCH DIODE - POS 35A 200V RIM

If I were to do this again, I would probably order my bearing elsewhere. The ones I installed were some Chinese brand. Not that there's anything wrong with that, but if I know the NSK ones lasted 100K+ miles, I'd be pretty sure that another set of NSK's would get me past 200K miles. Wagner was very helpful on the phone and although they primarily deal with shops, they lent me a hand with my order.

I also ordered my Bosch voltage regulator from Porsche. I didn't want to take any chances on an aftermarket one.

Good luck. I hope this post helps someone out.

Vandit

Pretty awesome DIY! I just had mine rebuilt by an alternator shop. Now I know where my $140 went.

Marc Shaw

Well done - very informative.

What was the bill for parts from Wagner's?

Marc

Lorenfb

"I tested the diodes and they all checked out fine"

Actually, you can't fully test the diodes with the stator connected because of the low resistance
of the stator windings which results in all the diodes being in parallel. So the diode test only
can check for shorted diodes and not open diodes without removing the stator. The same
apples to testing the field diodes (3).

Next, the slip rings, even though new, need to be turned on a lathe to achieve concentricity
with the alternator shaft.

superdylan

Lorenfb,
A question about the new slip rings. Wouldn't the new voltage regulator brushes wear a concentric groove on the slip rings anyhow?

superdylan

Marc, the bill from Wagner was $75 for the parts I replaced. 8 new diodes are about $35 if you wanted to replace them. The price doesn't include a voltage regulator.