So before I bought the car a couple weeks ago, I knew that the pulleys were wobbling and there was a lot of squealing noise coming from the alternator/pulley area on startup. I tied back the belt sensor -- no change. So I ordered up all new pulleys, belts, shims, an alternator, and a fan hub bearing and dug in.

Here's the wobbling I eventually found:

https://www.youtube.com/watch?v=slfk...ature=youtu.be

Let's start from the beginning though:



The belts had five years and five thousand miles on them, all Porsche branded though not visible here.


A stack of hockey pucks worked nicely to keep the AC compressor and lines lifted up and out of the way.


Not air cooled anymore!




The pulley was really stuck to the mating surface on the fan. Took a rubber mallet and a large screwdriver to unstuck it. Gross corrosion.


Pulling the fan and hub off the alternator shaft. I later found a better pressing surface than a broken sawzall blade... the aluminum jack pad for my BMW worked great.


At this point I was regretting not making plans for powdercoating:


But a scrub in the kitchen sink cleaned it up very nicely:


Skipping ahead a bit, I ran into some QA issues with the Bosch rebuilt alternator. One of the long bolts was stuck slightly away from the housing, so I had to use a punch to unstick it. I presume this would've happened while tightening the nuts later, but better safe.


The bigger problem was that the screw for the brown wire (that dirty SOB) was reversed. Old alternator on the left with accessible grounding hole, new one on the right with comparatively inaccessible ground hole. I swapped holes on the new one, but this involved pulling the whole thing back out and installing a second time as I hadn't noticed before installing.


Here's where things got really frustrating. I installed the housing, alternator, and fan. When spinning the fan, the hub appeared to wobble compared to the pulley mating surface on the fan. WTF! Is the bearing not in square? Well no... I realized that the mating surface itself has some problems. One of the alignment pins is totally gone, the other one has worn into an oblong shape, and there's material mushroomed up out of one of the holes. In fact, the whole surface is taller on one side than the other, creating a wobble when the pulley is attached.





It's actually visible to the eye, but I confirmed it with calipers too. Ordered up a new fan from Sunset, and this story is to be continued...

Seems like the first repair on a new car always has to make you its bitch.

 

how the heck did that happen? good catch
looks like you may have needed a new fan anyways. looking forward to seeing conclusion.

many of us have had to do this debacle 2 - 3 times during our first go for different reasons. (like me)

 

PSA You may find this thread of value when doing a core exchange for a new or rebuilt alternator to see if your old alternator has the better insulator (you can salvage) or not.

https://rennlist.com/forums/993-foru...ound-wire.html

 

Thanks for the heads up. Indeed, my original alternator has the larger insulator and the rebuilt has the smaller one. I've already got everything in place and was about to ship the old alternator back, but it'll probably be worth the hassle to swap it over. Hopefully I can do it without needing to remove the alternator and fan housing again... damn brown wire.

 

Regarding the material that has mushroomed out one of the holes, can't you simply file that material down smooth with the machined face?
Try that and then see if the pulley half spins true.
It doesn't look to me like you need a new fan.

 

It's not just the material that's mushroomed out, the whole surface is crooked by nearly a millimeter from one side to the other. The whole thing would have to be machined down. I'm sure it could be done and I might eventually do it and keep it as a spare.

 

Where are you measuring the 1mm difference from side to side?
Your final picture shows differences in the casting, which are to be expected because it is a casting.
Only the machined face needs to be straight (perpendicular to the shaft).
Sorry if I am missing the issue - not convinced that you have one that can't easily be remedied.

 

The machined face is not completely perpendicular to the shaft. If you start at the shaft with a straight line going to one side of the machine face, and then the other, you get different heights. I tried photographing it better, but I'm pretty convinced this is causing the wobble, and it's not just the bit that's sticking up.



I can't really photograph it with my phone while holding a pair of calipers, but it's visibly out of whack in person. I'm returning a $140 fan hub bearing towards the $440 fan, so considering I just bought the car, I consider the $300 difference worth it to be sure it's done right.

And I salvaged the insulator from the original alternator -- thanks again!

 

Sounds right then. The face should be perpendicular.
Maybe a machine shop can address that and you will have a nice spare.
Damn that fan cleaned up nicely!
Good luck with your project.

 

I think this clarifies the issue better. Rotated the image until I could draw a straight line across the base of the flange, then another straight line across the face. Surely anything mated to this would wobble to an equal degree, especially a rotating assembly at high RPMs.

 

I really don't have anything to add on this subject, but a welcome to squidge. It's nice to have a new member in the forum who's into DIY - and backs it up solidly with documentation and images for others to learn from.

Good luck sorting out the wobble!

 

If you reface the fan you'll need to shim the pulley by whatever you take off the fan, otherwise the fan pulley won't align with the crankshaft pulley, which will increase the wear rate of the belt. If it was mine I wouldn't try to salvage it, even as a spare.
What kind of environment was the car kept in?

 

Good to know, I was wondering how that would affect things. It seems less like it would directly affect tension and more like it would affect the alignment of the belts vertically, maybe increasing the chance of throwing a belt? I'm leaning more towards keeping the fan around as a decoration or making a little fresh air fan for the garage.

It's a lifetime CA car.

And thanks, snowbird! Happy to add back to the forums of whatever car I'm wrenching on at the moment. It was BMWs previously, and DSMs before that. I hope to be a lifetime P-car owner from here on.

 

Ditto

 

I suspect that the surface under the flange is actually bent distorting the location of the flange.
That fan would make a lovely time piece!