My DIY IMS Bearing Upgrade and AOS Replacement
#1
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I bought a 2000 996 Cab this summer with 65k miles on it well aware of the IMS issue. I planned all along to do the LN Engineering upgrade over the winter and the time has now come to do it. I'll post as much detail as I can as I go along and I welcome and encourage everyone's support, advise and assistance.
I am planning to replace the AOS at the same time and will look at the wear pads, chains and chain tensioners as I go along. I replaced the water pump a few weeks ago.
I believe in proactively addressing weak points with any car I have. For example, I recently sold a 2001 Jag XJR that I replaced the secondary chain tensioners on. Like the M96, the 4.0 liter supercharged V-8 Jag engine suffered a potentially fatal flaw. The original secondary chain tensioners had a plastic body that was prone to cracking and loss of tension resulting in catastrophic failure. Jag refused to replace them except when the engine failed and then only under warranty. Owner outrage, talk of class action lawsuits, etc. Same as the M96. I found that both of my secondary chain tensioners were badly cracked at 60k miles and would have failed eventually. Jag upgraded the secondary chain tensioners 3 times during the production of this series. The final chain tensioner body that I installed was metal. (If you think Porsche parts are expensive, price out some OEM Jag parts!)
I love my 996 and look forward to many happy years with it. Again, everyone who has done the IMS upgrade themselves, please jump in. I'd really appreciate any help you can offer.
I am planning to replace the AOS at the same time and will look at the wear pads, chains and chain tensioners as I go along. I replaced the water pump a few weeks ago.
I believe in proactively addressing weak points with any car I have. For example, I recently sold a 2001 Jag XJR that I replaced the secondary chain tensioners on. Like the M96, the 4.0 liter supercharged V-8 Jag engine suffered a potentially fatal flaw. The original secondary chain tensioners had a plastic body that was prone to cracking and loss of tension resulting in catastrophic failure. Jag refused to replace them except when the engine failed and then only under warranty. Owner outrage, talk of class action lawsuits, etc. Same as the M96. I found that both of my secondary chain tensioners were badly cracked at 60k miles and would have failed eventually. Jag upgraded the secondary chain tensioners 3 times during the production of this series. The final chain tensioner body that I installed was metal. (If you think Porsche parts are expensive, price out some OEM Jag parts!)
I love my 996 and look forward to many happy years with it. Again, everyone who has done the IMS upgrade themselves, please jump in. I'd really appreciate any help you can offer.
#2
Three Wheelin'
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hey pter - there's one very well done DIY post on this board by shark attack. Lot's of pictures included and he made his own tools. Last year we did a Porsche Club tech session over at SCAN where the IMS bearing was replaced, too bad you missed it, that would have been helpful I would think.
Getting the transmission out is the hard part. The bearing replacement is relatively simple in comparison.
Good luck, I'm sure there's a club member or two out here that would like to come and have a look/lend a hand if your interested. Me being one.
Getting the transmission out is the hard part. The bearing replacement is relatively simple in comparison.
Good luck, I'm sure there's a club member or two out here that would like to come and have a look/lend a hand if your interested. Me being one.
#4
Three Wheelin'
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I've just done IMS & AOS as well and documented the job/notes/tips/trivia at this link.
http://www.oz951.com/public/enginedrop.htm
Good luck.
http://www.oz951.com/public/enginedrop.htm
Good luck.
#7
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Thread Starter
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hey pter - there's one very well done DIY post on this board by shark attack. Lot's of pictures included and he made his own tools. Last year we did a Porsche Club tech session over at SCAN where the IMS bearing was replaced, too bad you missed it, that would have been helpful I would think.
Getting the transmission out is the hard part. The bearing replacement is relatively simple in comparison.
Good luck, I'm sure there's a club member or two out here that would like to come and have a look/lend a hand if your interested. Me being one.
Getting the transmission out is the hard part. The bearing replacement is relatively simple in comparison.
Good luck, I'm sure there's a club member or two out here that would like to come and have a look/lend a hand if your interested. Me being one.
I was hoping to do the AOS from the bottom with the tranny off. Anybody done this?
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#8
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#10
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Pic 1. First thing. Get the car in the air. I was dubious about doing a bunch of work and relying on jack stands alone. I just wasn't comfortable with it and I wanted more room to work. So I built up some wheel stands to get the car in the air. I'll put the back on jack stands with the wheel stands as back-up.
Pic 2. Since I had to wait for my jack stands to show up, I skipped unbolting the transaxles for now and got on with the other items. Unhooked the linkage. Pliers to squeeze clips and remove linkage from brackets. Two flat head screw drivers to pry linkage from ball sockets. Pretty easy.
Pic 3. Removed the clutch slave. It was a pain, but not too bad. I found a 13 mm wrench worked best to get the lower bolt started. Long extensions and swivel and lots of patience.
Pic 4. Drained the tranny fluid and the engine oil. During my first oil change 3000 miles ago I installed a magnetic drain plug on the oil pan. This was my first look at it. It had a light coating of fine metal powder on it. No shavings, just a very fine powder. Any thoughts?
I then loosened the transmission bolts and brackets and got ready to drop the tranny when the jack stands show up. They showed up late tonight (borrowed from a friend) but I had a commitment to do some charity work so that was it for today.
Pic 2. Since I had to wait for my jack stands to show up, I skipped unbolting the transaxles for now and got on with the other items. Unhooked the linkage. Pliers to squeeze clips and remove linkage from brackets. Two flat head screw drivers to pry linkage from ball sockets. Pretty easy.
Pic 3. Removed the clutch slave. It was a pain, but not too bad. I found a 13 mm wrench worked best to get the lower bolt started. Long extensions and swivel and lots of patience.
Pic 4. Drained the tranny fluid and the engine oil. During my first oil change 3000 miles ago I installed a magnetic drain plug on the oil pan. This was my first look at it. It had a light coating of fine metal powder on it. No shavings, just a very fine powder. Any thoughts?
I then loosened the transmission bolts and brackets and got ready to drop the tranny when the jack stands show up. They showed up late tonight (borrowed from a friend) but I had a commitment to do some charity work so that was it for today.
#11
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I will look at the upper pads by pulling off the cam covers and call it from there. If she has to come out, she will come out.
#13
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Whew! Getting the engine and tranny separated was lot more work than I expected. Based on the shallow depth of the IMS flange, it looks like I have a double row bearing. The RMS is not leaking but the IMS flange is. The RMS and clutch were replaced by the previous owner earlier this year and look good. (Too bad they didn't do the IMS upgrade)
I'll post more pics tomorrow. Thanks to everyone for their help! Much appreciated!
I'll post more pics tomorrow. Thanks to everyone for their help! Much appreciated!
#14
Three Wheelin'
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Nice work.
Did you lower the front of the engine by that one inch to gain better access to the top bolt on the transaxle?
I see a bit of oil there under the IMS flange. Assume that's a leaking flange seal?
More pics !!! kinda just kidding though...I know how hard it is when you're in the middle of the job to just stop and photograph...especially with oily hands and all.
In fact any pics and documentation is well appreciated
Did you lower the front of the engine by that one inch to gain better access to the top bolt on the transaxle?
I see a bit of oil there under the IMS flange. Assume that's a leaking flange seal?
More pics !!! kinda just kidding though...I know how hard it is when you're in the middle of the job to just stop and photograph...especially with oily hands and all.
In fact any pics and documentation is well appreciated