I found myself with enough parts laying around to put together a rebuilt alternator. I knew that front bearing was noisy so set out to replace the bearings and other "while you are in there" parts.
I was inspired by Homeoboxter’s project starting in post #66 here:
https://986forum.com/forums/show-tell-gallery/73917-blue-boxster-resurrection-project-4.html
This video helped me realise that the drive pulley was defective… it was frozen solid.
https://www.youtube.com/@WestronicsIrl
To remove the my pulley I bought a 33T Alternator Removal Socket and a 10mm triple-square bit. It took considerable force to loosen it.
This video is for Volvo alternator, but most of it applies to the Porsche unit. It is very detailed.
https://www.youtube.com/watch?v=05ZMnrtTFzE
NB - the rear bearing holder on my alternator is black and must be placed before installing the back cover. I have not found a video that shows this step clearly.
I also had to drill out the bearing holder screws. They are M4x.7 and 16mm long would be enough. I bought 25mm and cut the excess off.
Since I don’t have a press I used a bearing puller on the front bearing,
In effect I was pulling the alternator case off the bearing.
At first I reinstalled the pulley, with a piece of metal to prevent the bolt of the puller contacting the end of the shaft (in this case the steam valve of an old pressure cooker). The pulley was not screwed all the way down so it would not immediately contact the alternator case. As the bearing started to move I screwed the pulley out to provide more clearance. Here is my installation.
It would perhaps be easier to use a 30mm socket instead of the pulley.
I used my dremel clone to cut the slip ring and it broke off easily.
I had intended to change the brushes in the voltage regulator, but the regulator was not designed to make replacing the brushes easy. The grounding tab that is supposed to be just to the right of the brushes is broken off... I will have to find a way to replace it.
According to this video the brushes can be changed... with difficulty.
https://www.youtube.com/watch?v=b-ZRpGTVdSQ
Since my brushes still have some life in them I decided to reinstall the regulator as is.
Given this is a spare alternator I don’t plan on buying a pulley right away, they are a bit pricey. The parts kits with bearings, a new slip ring and new brushes are readily available.
Other videos if you want to watch more…
Front bearing removal was explained here:
https://www.youtube.com/watch?v=sTTfemu_gcY&t=797s
The rear bearing and slip ring:
https://www.youtube.com/watch?v=DhjT6qKUOBc
Boxster
Linear Mode
