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YOUR RESEARCHRebuilding the alternator - 986 Forum - The Community for Porsche Boxster & Cayman Owners
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Install rear bearing (using the freezer and heating again)
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Performed · outcome unconfirmed · Original poster
Aftter soldering the wires onto the slip ring base (those wires are more resistant than they look) I installed the rear bearing (using the freezer and heating again).
Rebuilding the alternator - 986 Forum - The Community for Porsche Boxster & Cayman Owners
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Leading evidence: 'Install rear bearing (using the freezer and heating again)' (no explicit attributable resolution; this is a reported action or suggestion). Across 1 matching discussions, the most frequently mentioned possible cause is 'drill' (1 discussions; 0 report identifying it and 1 suggest it). The most frequently discussed action is 'Check its pulley also' (1 discussions). For that action, 0 discussions report a resolution and 0 report an unsuccessful attempt. No action has an explicit, attributable resolution report under the current rules. These are forum reports and suggestions, not a confirmed diagnosis.
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Explicit resolution reports before identified causes, performed actions and suggestions. Within each level, matching component labels precede direct query mentions and inherited thread context; successful versus unsuccessful discussion counts, owner confirmations and independent discussion support determine order. This is not a probability of success.
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Performed · outcome unconfirmed · Original poster
I installed the regulator and now I have to test it.
Rebuilding the alternator - 986 Forum - The Community for Porsche Boxster & Cayman Owners
Use bearing puller
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Performed · outcome unconfirmed · Original poster
Since I don’t have a press I used a bearing puller on the front bearing,
Rebuilding the alternator - 986 Forum - The Community for Porsche Boxster & Cayman Owners
Use dremel clone
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Performed · outcome unconfirmed · Original poster
I used my dremel clone to cut the slip ring and it broke off easily.
Rebuilding the alternator - 986 Forum - The Community for Porsche Boxster & Cayman Owners
Use rubber hammer and a large c clamp
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Performed · outcome unconfirmed · Original poster
I used a rubber hammer and a large C clamp to get them close enough together to insert the four screws...
Rebuilding the alternator - 986 Forum - The Community for Porsche Boxster & Cayman Owners
Install rear bearing (using the freezer and heating again)
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Performed · outcome unconfirmed · Original poster
Aftter soldering the wires onto the slip ring base (those wires are more resistant than they look) I installed the rear bearing (using the freezer and heating again).
Rebuilding the alternator - 986 Forum - The Community for Porsche Boxster & Cayman Owners
Replace slip ring and resolder the terminals
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Suggestion
When you replace the slip ring and resolder the terminals to the ends of the coil, make sure you use a small amount of soldering iron but try to build it up to last.
Rebuilding the alternator - 986 Forum - The Community for Porsche Boxster & Cayman Owners
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4 eligible posts · 0 unverified posts · 1 discussions match the subject in their title or opening post.
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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
I followed the Volvo alternator video mentioned in the first post. A few notes on my experience.
The front bearing went into the front casing easily after I heated the front casing and put the bearing in the freezer. Then, after installing the bearing holder, I put the rotor in the freezer and heated the bearing and was able to install the rotor into the casing.
I was worried about tapping the slip ring on with those skinny legs between the rings and the base, but it is the top, under the slip rings, that you are forcing on to the shaft splines so there is very little force transmitted by the "legs".
Aftter soldering the wires onto the slip ring base (those wires are more resistant than they look) I installed the rear bearing (using the freezer and heating again).
Next the rear bearing holder is inserted in the rear cover, tabs fit into grooves to properly align it. It was tight enough that I had to tap it into place.
(sorry for the fuzzy photo)
Next the front and rear covers where assembled. I used a rubber hammer and a large C clamp to get them close enough together to insert the four screws... then the screws pulled it tight. Make sure the covers are properly aligned and not cocked on way or the other.
I installed the regulator and now I have to test it.
Nice and easy project! When you replace the slip ring and resolder the terminals to the ends of the coil, make sure you use a small amount of soldering iron but try to build it up to last. The pulley is about 3-times smaller in diameter relative to the one on the crankshaft, meaning it can spin well over 10.000 rpm, on average! I had to redo the soldering on mine when it snapped after a few thousand miles during acceleration
.
Not too difficult it is true. The alternator is back together now and I have been trying to test it (there are several Youtube videos on how to do that) but I am getting no voltage to the attached battery. I suspect the the drill that I am using to rotate the rotor does not turn fast enough. I calculate that the alternator turns about 2.5 times the speed of the crankshaft so at an idle of 700 rpm the alternator should turn at 1720 rpm. My drill gives about 1200 rpm. So I am trying to think of a way to get it to turn faster with what I have available.
Because the pulley I took off the alternator was seized I decided to verify the pulley on the alternator that is installed in my base Boxster that I am selling... and found it was seized also, so I bought a new pulley and installed it in the car. When my Boxster S comes out of winter storage I will check its pulley also. It seems that that is something worth doing when the front cover is off the engine.
This is a source reference. Confirm exact model applicability in the original material.
