Perry 951

I e-mailed Steve yesterday to check on my set of bearings, he replied within a few hours. He sent them out the same day I purchased them and tracking shows they should be at my place this morning. Pretty good service!

He assured me that these are quality parts. Cost is not very high because he has access to the MFG stream and gets them with a small mark up. He then marks up a little and sells them here and there as a part time job.

Hell, if they only last 1/2 the 130K the originals did, we got our moneys worth!

Pauerman

While you've got access, don't forget to test the diode bridge with a multimeter.

Van

Can you tell me exactly what I'd be looking for?

Perry 951

Acutally did a diode test on the bench tester at my store (Advance Auto). It all checked fine, except for the noisy bearings and flaky regulator.

SOP on testing it off a rig would be helpful. Thanks!

aribop

Brian, can you post contact information for Steve...I need to do this as well.
Thanks.

Perry 951

In Van's write up.

http://stores.ebay.com/PACIFIC-NORTH-WEST-BEARING

Pauerman

In your second picture, it's the black plastic and partial metal gizmo that attaches to the field wiring (4 wires). The diodes are the circular deals on the bridge - they transform the A/C generated by the field and armature into D/C. Use a multimeter with a diode checking option to check if diodes are still functioning normally.

Jfrahm

I want to rebuild my 928 alternator and try out this diode mod:

http://www.detomaso.nu/~thomast/alternator/

Looks like a cheap and easy way to get a bit more voltage.

-Joel.

aribop

I'm a dumbass! Please excuse the wasted bandwidth.

How about posting the part numbers when you get them?

Van

I got that alternator back together. It went together nicely -- the Turkish bearings were a perfect fit.

Here are pictures of the reassembly process.

(I poked around on that back plate with my multi-meter a bunch, but still wasn't really sure what I was looking for... so it seems all is fine. once I get it installed, then I'll be able to test it.)

Speaking of the installation, removing the old one from the engine compartment is no small chore (on a turbo). There was another thread about the complexity of removing a transmission, and frankly, I'd rate an alternator change as more difficult than a tranaxle. I really know my way around these cars, and I'd say it took almost 3 hours to get the alternator OUT!

Enjoy the pics:

Dynamite 76

Thanks for the great write-up. What is this part? My alternator is putting out 23 volts AC. I have a new regulator on the way, but no means/tools to do a complete rebuild at the moment.

ibkevin

Excellent DIY pictorial, thanks Van!

Van

I'm not sure what that is... my understanding of electronics is medeocre at best.

My hunch is that it's some sort of capacitor -- I know that for an alternator to start charging, the field needs to be supplied with a 12v current (that's what the little wire is), once the field is "generated", the alternator's electricity keeps the field current going. The field current induces a current in the stator (part that spins) by all of that electro-magnetic hoey...

Anyhow, back to my hunch, that capacitor, if it is a capacitor, may play a part in electrifying the field, or perhaps in discharging the field when the stator stops spinning. I'm really making all this up, so take it for what it's worth.

I can more factually tell you that what turns AC current into DC current is a bridge rectifier -- AC current is a sin wave, so the rectifier takes the bottom half of the sin wave and flips it upside down. (You can do a google search, I'm sure, to find diagrams). Anyhow, the AC current sin wave goes from -12 to +12 -- a total potential of 24V AC. Once the bottom side of the graph is flipped up, you have twice the number of peaks at +12, an zero peaks on the negative side of the graph. This gives you 12V DC.

So, you have some problem with the bridge rectifier -- is this the "voltage regulator"? I'm not 100% sure, but hopefully someone will chime in and let you know.

Good luck!

sillbeer

That rear part is the "condenser" to try and cancel out radio interference from the alternator. Awesome write up, BTW!!!

Van

Well, my A/C delete-and-alternator rebuild is complete. I was surprised how much had to come apart to change the alternator bracket! It was no small job! The intake hard tubes, air box, J boot, and turbo hose all had to come off. Then I had to undo the turbo water pump and one other coolant line to get the old alternator out!

The A/C delete bracket went in without a problem, but I couldn't get the long pivot bolt for the alternator back in until I took off the bolts that hold the radiator fans in place to jiggle that around! Finally, I got it all together (minus the alternator cooling duct and funnel -- I have to do some fabricating to make that work).

Anyhow, it's in and should be much easier to change in the future, if I ever need to.

Oh, I used extra washers as spacers for the top two alternator bracket bolts -- this way it still connects to that intake support bracket and the engine lift ring (which supports a coolant hose).