Removing And Replacing The Alternator

[Loren]

Removing and Replacing the Alternator

---

Removal 1. Disconnect the battery and cover terminal or battery. Undo the fastening screw for the air cleaner housing and the hose clamp on the throttle body. 2. Disconnect the electrical plug connection on the air flow sensor and remove the complete air cleaner assembly. 3. Relieve the drive belt at the tensioning pulley and remove the belt. 4. Disconnect the electrical plug connection on the vacuum switchover valve and unclip the switchover valve from the holder. 5. Undo the holder at the

---

• Author
  Loren
• Category
  Carrera (996) - Common Fixes and Repairs
• Submitted
  04/25/2010 08:37 AM
• Updated
  07/19/2012 08:19 AM

 

[CMiYC]

Just from looking at the engine bay, I'm not seeing why I need the multiple-tooth adapter. I have a 2004 CS4 w/ Manual.

if needed is this tool available at a Sears or AutoZone-type store? I searched the web for the official part and found several suppliers, but was hoping to get this done this weekend.

Edited September 17, 2010 by CMiYC

[JFP in PA]

Tool actually looks like this, and you won't find it at Sears (or most any other tool outlet). Get it online:

[CMiYC]

Thanks. It took me a while to understand what it was needed for, since I didn't realize there was a dust cover on the Alternator's Pulley.

[CMiYC]

Originally posted a question about a trick to get the generator out (or in).

Was about to use two chisels as levers to move it around. I wasn't expecting to do so much man handling, but it seemed to work.

Edited September 18, 2010 by CMiYC

[Karl996]

Please someone help !!!

Trying to get the alternator out and I'm stuck.

I cannot seem to rotate it clockwise enough for the left bolt hole to clear.

The top of the alternator hits the underside of the inlet runner.

I'm wondering if there is something I need to do which is not mentioned in the tutorial.

It's a 2002 3.6 C2 manual. Right hand drive.

Many many thanks in advance

[logray]

Try going anti-clockwise, so the piece on the alternator that is held by the long bolt with the idle pulley clears the mount.

[Karl996]

Thanks logray.

It's 1 in the morning here so I'll give it a try tomorrow night after work.

Will update.......

[Karl996]

So here's the update - which I am not proud of :(

After 2 hours of trying last night (with a friend who is a mechanical engineer) I had to admit defeat and surrender.

There was no way I was going to get the alternator out.

Decided to put everything back together.

At least I have a new drive belt and can say I've worked on the rear of the car for the 1st time :D

[logray]

LOL, well at least you tried.

I've used a block of wood and a long pry bar to "coax" the alternator out of position.

Of course you want to do this carefully as to not damage any fins or the alternator housing itself.

[Gatorkev73]

Okay, I'm stuck...Trying to clear the alternator out and mine is hung up on the right side where the pully bolt attaches. Any suggestions? Also, my new alternator has the pully already attached...I don't see the need for the socket.

[wxseed]

I recently replaced my voltage regulator because the car wasn't charging, it's now working great. I'll share a couple of pointers I learned along the way. One of the most important items when removing the alternator is to drift the bushing, that the long bolt threads into, back as far as possible. Using penetrating oil and a hammer I could only get the bushing back about 1mm. The farther you can get the bushing back the more room you have to rotate and clear the alt bracket. It took me about 1.5 hours to get the alt out. I understand why the alt needs to be rotated clockwise as per the manual but I ended up getting it out by rotating counter clockwise. Along the way the oil filler tube broke off, it was really brittle and I managed to break this fitting with an errant blow by the hammer. http://www.renntech.org/forums/topic/34150-coolant-problem/ With the alternator out of the car I heated the alt housing around the bushing with a propane torch, gave the bushing a tap and it easliy moved back. After changing the regulator, re-installing the alt took me about 30 minutes.

One pointer on changing the oil fill tube: I was able to do it with the alt out, I didn't need to remove the throttle body BUT it is very cramped, I used a 75mm wobble extension on the back bolt. Make sure you tighten the bolts up evenly or the tube won't fit flush with the crankcase, and have a magnet handy for when you drop the back bolt and can't see it to find it !!

This is a good link on what voltage reg works, I used one for a 2001 VW. http://forums.pelicanparts.com/porsche-996-997-forum/408495-alternator-repair-regulator-replacement.html

I'll post pics if someone tells me how .....

[JFP in PA]

I recently replaced my voltage regulator because the car wasn't charging, it's now working great. I'll share a couple of pointers I learned along the way. One of the most important items when removing the alternator is to drift the bushing, that the long bolt threads into, back as far as possible. Using penetrating oil and a hammer I could only get the bushing back about 1mm. The farther you can get the bushing back the more room you have to rotate and clear the alt bracket. It took me about 1.5 hours to get the alt out. I understand why the alt needs to be rotated clockwise as per the manual but I ended up getting it out by rotating counter clockwise. Along the way the oil filler tube broke off, it was really brittle and I managed to break this fitting with an errant blow by the hammer. http://www.renntech....oolant-problem/ With the alternator out of the car I heated the alt housing around the bushing with a propane torch, gave the bushing a tap and it easliy moved back. After changing the regulator, re-installing the alt took me about 30 minutes.

.....

Open the link in Loren's original posting and read item #7; that is all you need to do to move the bushing rearward and remove the alternator..................

[wxseed]

JFP thanks for the response,

Edited October 26, 2020 by wxseed
correction

[JFP in PA]

JFP thanks for the response, If only it were that easy ..... not sure if you've removed the alt before or not but I followed the instructions as posted. I also went a step further and went to the local Porsche dealer here in Toronto, as luck would have it a tech was taking an alt off a 996. He walked me through the process and explained how seized the bushing can become and to be carefull not to break the alt housing pounding on it with a hammer. The bushing on my car was seized solid after 11 years and 125,000 km including Canadain winter driving. The point I was making, and why I was sharing my experience is to make it easier for others attempting this job. Heating up the aluminum housing allows you to easily push the bushing back instead of pounding on it with a hammer and potentially breaking the housing ......

I own an independent shop, and we pull out a fair number of M96/97 Porsche alternators just about every day; we have never had to heat up an alternator case, or pound on it with anything. Loosening the bolt and giving it a tap or two is all that was necessary in all the years we have been doing it; the bushing only needs to move a thousandth or two for the alternator to come right out. I have no idea why you had such a problem, but we never have seen the need to risk heating up an alloy housing or beating on it.

Edited September 14, 2012 by JFP in PA

[Silver_TT]

+1 to what JFP is saying

I don't mean to interject but I recently went through the exact same thing with my voltage regulator / alternator and my car is also "old" -- a 2002 C4S -- and has seen cold and snow. My guess is that you didn't have the bushing out enough from the flange. It literally just takes 2-3 twists and then a tap with a hammer (with a buffer such as wood to not damage the bolt..unless you have a deadblow hammer). I made the same mistake when I followed Loren's instructions but wasn't super careful to follow it word-for-word on the first try. You won't break the housing with the force from a hammer because eventhough it's alumimum you're not talking about going wild on it. All it takes is a couple good but powerful taps to push that bushing back from the flange.

That said, I just went through this same thing as I said and I agree it's a bit of a pain to get the alternator off the first time you try. Once I understood what I stated above I know I can do it much faster next time and without so much blood, sweat, and tears as I spent on the first try. The first time I tried it and that bushing was still blocked by that flange, I also though that it was fused to the metal or something.

Either way, glad you got it sorted and you learned something from it so that's what's important!

cheers 

Edited November 5, 2016 by Silver_TT

[carsareart]

I was able to work mine out with out problems. It was tight but doable. Mine is a tip and I have a clutch type pulley. Is this normal? 

[Silver_TT]

I believe only the manual uses the freewheel pulley version if you go by the book.  That said, you probably don't need to worry, I don't think it would hurt it to use one on a tiptronic  (although the reverse, using one without the freewheel pulley on a manual transmission, would be trouble).

[carsareart]

Cool, that is good to know. how does this pulley help the engine? 

[Silver_TT]

You can google sprag clutch for even more info, but it's there to help allow the transmission to smoothly change gears under load.

 

Tiptronics are not as likely to have abrupt RPM changes because it's the computer controlling the shifting, not a human, which is the reason it doesn't use the clutching pulley.

 

Hope that helps.

Edited November 6, 2016 by Silver_TT

[docoscar]

I replaced the alternator this weekend on my 996 C2-03. I followed Loren's guide aswell as the DIY guide on Pelicanparts.com. In addition to what is said there, I have the following tips.

Loosen the lower left bolt, but keep it in place. After having tapped the long bolt on the right, remove it completely. Spray WD40 on the bushing. After that, and here's the trick, gently push the alternator counter clockwise using a crowbar squeezed in under the alternator using the metal plate, that holds the left bolt, as support. I found it to be very useful and the extra leverage made it very easy. All in all it took me three hours from A to Z, whereof half of that time was spent trying to move the alternator before I tried the crowbar. Good luck!