Good news! My clutch failed....pretty sure.

Hate to break away from the real technical content like seeing how much lettering one can cram on the back of a 996, but on the way home this evening I go for second gear and the clutch pedal kind of flops to the floor and I can barely engage the gear. The pedal still goes up and down, although with a wimpy feel like it's just the helper spring working, and the lever balks hard whenever I shift. I got home and verified that the fluid level in the reservoir is still topped up, and thought back to only a few months ago when my wife's Audi Allroad exhibited almost identical symptoms. In that case it was the throwout collar/bearing. I ended up having the whole shebang replaced though, clutch, flywheel - everything. Anyway - I will go under soon to verify that the slave is making a full stroke when the pedal is depressed, and if so, it's time to remove the trans and get to work. At this point I'm thinking: Clutch (nach) LNE IMS (providing my reman motor isn't a big nut setup) LWFW ??? - will try to find out if anymore crankshafts have broken recently. RS Motor mounts. Fluid change. Re and re the CV joints. RMS ??? or should I leave well enough alone? It's not leaking at present. I'll take a few snaps. I probably won't move too quickly. I'm a busy boy these days.

If the RMS isn't leaking, I'd probably leave it alone. Mine goes to the dealer on Friday as it appears to have a leak from between the engine and the trans.

Well, that's step one done. Stable like a rock. I might have to move the rear jackstands out to the jack pads ahead of the rear wheels to give myself room to move, but then again, maybe not. Either way, it will be simple enough. I notice a very minor bit of weapage on the bottom of the engine where the trans mounts up. It will be interesting to see if that's the IMS flange seal or the RMS. This car has done 190,000 kilometers already eh. 120,000 on a reman motor installed in early 2005 (under warranty long before I owned it). No word on if it got a new clutch at that time also. Oh yeah..I plan to do the 2nd gear detent mod. I've always felt that my second gear wasn't landing deeply enough although I've never had a pop-out or anything like that. Just a feeling.

While you're up there, I would take it out of reverse and shut her down....

I like the Persian carpet mod. Very cool. You guys in Vancouver know how to treat your cars!

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My tech replaced the RMS on the theory that it couldn't hurt and very minimal cost.

Sounds like a broken pressure plate.

Where have you been Ahmet? Haven't seen you posting of late.

I would replace the AOS while you are there.

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Well, if the 996 breaks down, maybe he takes it to work? Good luck getting her sorted!

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I hope so - I'd like to feel that I got my money's worth out of this clutch. I picked the carpet up last year. A neighbour was renovating and gave it away for free. It's actually really nice. Classes the joint up and I don't have to lie on the cold concrete. I do hope it doesn't interfere with moving jacks and what not around but I think it will be ok. Actually my garage is still in construction stage. I am going to install a hoist this summer, so timing isn't perfect...but at least I don't have to do the job outside in the carport. Taking the carpet to work was never an option. It rains a lot here and the water screws up the aerodynamics. I am riding my motorcycle instead. AOS - yes was thinking of this. I'm just heading over to Pelican now - starting a shopping cart.

I would not install a LWFW without 1st having it dynamicly balanced. You are removing the only harmonic dampner on the engine & introducing an additional vibration source. I have the proper fixture for balancing flywheels if you go this route. (good idea for DMFW & pressure plate also)

How do you clean that nice rug, assuming you spill oil or any other fluid on it??

I'm not classy enough to do the rug mod. Corrugated cardboard is more my style, just toss when it gets dirty. I'm not talented enough to keep a spotless garage.

Could this be your clutch slave, not the clutch itself?

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Not too worried about spills - it's my shop rug after all - but the plan is to hang it up outside during hot weather, spray some carpet cleaner on it and power wash it. I've already had some small spills - no biggee. Yes indeed it could..that or the clutch master, but my reservoir hasn't dropped down at all, which I would expect if either of those components failed. The plan before tearing into thing too heavy is to verify that pushing in the clutch produces a full stroke at the slave where it actuates the clutch lever. I'll look for leaks at both the master and the slave also.

If the seal is gone the piston could push through without leaking, just bypass the fluid,if that makes sense!

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The back of the cylinder is (typically) open, covered by a rubber dust boot. If the piston pushed through, then fluid would get in behind the piston and fill the boot. Then when the piston returned, it would push fluid out, past the dust boot This woudl present as a leak. Given the number of clutch pumps I made after the pedal first dropped I would expect a leak like that to be very obvious and I would also expect my reservoir level to be down. But - your thinking is correct - I need to verify the hydraulics are nominal before putting wrenches and hex bits to bolt heads.

A new RMS (latest version) is about $30. It would be silly not to install a new one while you're in there.

+1 I think the RMS has gone through one or two revisions (improvements) since the one installed on your car. Would be worth it to replace.

bump... where you at now? would like to come by and have a look.

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The car is up in the air (maybe even too high up in the air), the belly pans are off. Tonight I will verify it's not simply hydraulics maybe get as far as unbolting the drive shafts. Tomorrow or Sunday I will drop the transmission. I have 28 inches of 3/8 extensions in hand - I've read all the threads and looked at all the photos and I've even read the Porsche Workshop manual. Not anticipating any problems and I am prepared mentally for the difficult to reach stuff. You are always welcome Geoff - the beers you brought over last time are still on the shop floor.

OK lads - time for a silly question: How can I be sure that the slave is functioning properly? As it turns out, the slave piston inters directly into the bell housing so I can't observe it directly. I can tell you this though: 1) The master appears sound. There is no evidence whatsoever of leaking around the rubber boot inside the car. 2) I can hear the fluid flowing when the clutch pedal is depressed. Kind of a whoosing squishing sound. 3) Clutch pedal goes to the floor, comes up half way, then stops but if you give it a little nudge, the clutch helper spring brings the pedal up the rest of the way. 4) no evidence of leaks at the bell housing - no apparent drop in fluid level in the reservoir. Here's some highres photos to amuse you while you ponder my question. First is the car at it's max height. It may be too high. Not in this photo is my snow tires and wheels stacked under the rear of the car to save me if it comes off the jackstands - I will be making it 100% safe before I start pushing and pulling hard. Second and third is the staining I mentioned earlier. In fact you can see it isn't where the trans mounts up to the engine. It's at the rear of the oil sump plate. Just weepage - no leakage. I think you can also see why my question earlier was unnecessary. The longitudinal mount has to come off to allow the trans to move back away from teh motor. Fourth is my daily transportation now the car is down. Would be nice if it would stop raining for a few hours. Thanks for considering my question.

Duh. The slave has to come out regardless because if it's bad it will need re and re. If its good, then it has to come off to replace the clutch. It should be obvious if its leaking once its in my hand.

Right - that's the slave out. No sign of leakage. I puled the boot back to confirm. The way it works, there's no way it could be leaking past the seal without also leaking directly out. Removal wasn't easy, it wasn't hard. One skinned knuckle, took less than an hour. 13 mm socket. Top tips: 1) The top bolt was easy with a universal joint and a 3 inch extension..maybe it was a six inch extension. Either way it was easy. 2) For the bottom I went in from the wheel well (see photo) with: socket 3 inch extension universal 3 inch extension 18 inch extension ratchet. ***3) I had unclipped the hard line from it's bracket already, but once I started winding out the bottom bolt by hand I realized it would be about 10x easier without the damned bracket still bolted to the trans. The 13 mm bolt heads are right there - it came off in 30 seconds and about then I realized the top top tip is to remove this bracket as early as possible for clearance. Note that I wound the bolts back into the mounting holes so I won't misplace them. Old habit. Therefore it's not obvious where the bracket mounted in my pictures but look close and it's easy to figure out. With regards re-installation - I'm pretty sure it will be easier to disconnect the hydraulic line and bolt the slave to the trans before the trans goes back in. Bleeding the clutch will be easier than getting those bolts torqued with the trans in place. Here's the photographs:

Aargh. On line research suggeting master can fail without leaking. Dad Gamb it. How am I supposed to confirm this issue?

The clutch master etc should work exactly the same as a brake master and they will fail without a leak,I know I've done that,I believe that if it was the clutch itself that the pedal will work as before but the clutch will not disengege, I had that happen before as well, a long time ago so I am trying to remember how it went, but one shift it worked and the next the clutch wouldn't let go. Not sure how to tell for sure how to check if it is one or the other, try renntech.org they are very good at answering questions, the moderator is a Porsche Tech I think. Good luck with this.

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Thanks heli - I posted on Renntech and we'll wait to see if Loren picks it up. Good advice. I want to do the big job because our friend billyboy over in Tsawassen lost a motor to the IMSB last week. I'm feeling nervous. On the other hand, I don't want to throw away a good clutch. I'll tell you, I'm far enough in now that I might just do the job even if it does turn out to be a hydraulic issue. cheers

Good luck, I'll be following to see how this turns out.

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Clutch slave cylinders are pretty cheap so you might want to replace it anyway, think about how long it's going to be before you want to do this exercise again. If clutch pedal is pressed while cylinder is disconnected it will damage it.

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Good point and yes, I'm aware that I can't push the clutch pedal now that the slave is out. I'm thinking more that if it's hydraulic then it's the master not the slave, but you're right, the slave is almost guaranteed to fail sometime in the next 100,000 miles and for the few bucks now it will save me pain and suffering sometime when I am in my 50's, when I will be even less excited about removing the little bugger. Thinking now that if it was a sudden hydraulic failure that occurred last week then it's not likely that I would have been able to hold the clutch pedal down and be able to select a gear after any length of time. The pressure plate would have been pushing back on the hydraulics the whole time. Then again I'm 20% into the job so my mind is not letting me think purely rationally. One response on Renntech says that I should not be able to push the slave piston inwards if the hydraulics are good. I will check this now. I don't think though that this is a way to confirm good hydraulics, only a way to confirm bad hydraulics.

Hows this for a test: Removed the actuator rod from the slave. Pushed the piston all the way in and inserted a 3/8" punch into the piston where the rod normally rides. clamped the system so that the piston can't move out when the clutch pedal is depressed. Go inside the car and tried to press down the clutch pedal and it moved about an inch and stopped. I pushed pretty hard - but not enough to blow the seals obviously. Seems to me the hydraulics are good. What say you? Anyone?

Two things: I would not have done that. It's the pressure plate. Stop beating around the bush, the job isn't bad at all. :P Barn, I was never a big poster but I've just been working way too much of late. That and I wasn't happy w/my 996. Let's just say one thing led to another and it got a lot of attention as of late...

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Thanks Ahmet - I appreciate advice from the experienced. I am replacing the slave anyway so wasn't too worried about screwing it up. I'm not worried about the job so much, I'm fully prepared. I just didn't want to bolt it all back together and then find out it still doesn't work because the problem was the hydraulics. I plan to drop the transmission tomorrow - provided I can get my floor jack working again - had bit of a fluid leak....somewhat self induced. Long story. edit - Speaking of long stories - what happened with your 996? Do you still have one? Did something unsavory happen? Was it fun at least?

Exactly the same symptom as mine, when the pressure plate failed.

Right - that's the transmission out. With a hoist, and an awesome selection of wobble joint extensions, I can just barely imagine getting the top nut without dropping the engine an inch. For anyone thinking about doing this on their backs on the garage dropping the engine isn't just necessary - it is easily worth the tiny bit of effort and the little bit of thinking required. A big problem for me also was that after 120,000 km of driving rain, snow and shine the steel bolts had oxidized themselves nicely onto the aluminum trans housing. I had to lever the sh*t out of my ratchet every single time. I used both the handle from my floor jack and a box end wrench to get this done. Not all that easy or enjoyable to be honest. Separating the transmission from the engine took a lot of jiggling and pulling so make sure your engine brace is solid. Mine went together quick ( see photo) 6x6 screwed to a 2x10 base plate sitting on top of a 2x12. I have a hockey puck between the top of the 6x6 and the engine case. Here's the photos - I didn't take any during the hard work...kinda busy! Oh yeah - shout out to my good buddy and workmate GNR996 who lent a hand and some thinking energy.

Here's where my pressure plate cracked...in between those two fingers there:

Here are the photos of the RMS and IMSB flange before and after I cleaned them up. There was just clutch disc dust on both of them - no oil whatsoever. Notice anything unusual? That's right - the big nut on the IMSB shaft means this is a M97 upgraded engine. This IMSB can not be extracted from the outside of the engine. This upgrade was Porsche's internal answer to failing intermediate shaft bearings. For better or worse - this is the bearing that I am staying with for the long haul.

So the new plan is: 1) AASCO Light weight fly wheel. I have a refurbished and (importantly) balanced piece with new bolts lined up. My stock DMF is in good shape - I'll keep it in case I don't like the LWFW. 2) Stock clutch kit - included pressure plate, friction disc, throwout bearing. Will order a new throwout bearing collar too. 3) New slave cylinder - the old one has a ton of miles on it and I abused it a but during my troubleshooting phase. 4) Second gear detent mod/upgrade. Never liked how second gear landed. I have to figure out where to buy that. 5) New air oil separator. I shudder to think how painful that replacement is going to be. 6) An new RMS..providing I can find a good procedure and the tool necessary to do the job exactly right. My motor was clearly built during the start of the 997 series - so presumably the installed RMS is the latest and greatest. That's it..if I have any money left over I'm getting a set of RS motor mounts.

big nut huh... whats the data on the big nut motor failures?

I wouldn't change the RMS, it's the updated style and not leaking so why bother?

I remember when the same thing (symptoms) happened to me.....Ahmet said "most likely the pressure plate".....he replaced my clutch in one day......finding broken fingers on the pressure plate..... Did I say he knows these cars well?

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+1 on this especially without the install tool Also need a sprung hub clutch disc to go with the un damping flywheel. G-Box in Colorado sells the 2nd gear detent improver

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OK: 1) I'm going to build the tool...although I want to look at the factory tool to see just how trick it is. I won't be pulling the old seal out without first being 100% sure I can put the new on in without issue. 2) Spring centred disc eh? That's not something I planned on. Asking around it's recommended not required. I'm going to do some asking around on the forum here. 3) GBox - yes I figured that out too. Parts are ordered and on the way. I just have to figure out this clutch disc thing. It's a $600 part....same as the entire OEM clutch kit.

Sachs replacement clutch kit costs about $500. and is all you need. Anything else is a waste of your money....

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Oh geez, I would love a source for that kit JR. ++

subscribed

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Wholesaler SSF.... https://www.ssfautoparts.com/

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Thanks JR. SSF is wholesale only. Seem like nice people but they can't sell to the public, nor will they quote prices. I ended up going to AASCO for the sport pressure plate and spring centred disc. $1100 for those parts. Basically the same price as Pelican. Add $100 for the throwout bearing and the total is $1200 versus $650 for the OEM kit which is available everywhere. I have RS motor mounts coming from Suncoast too. Things should be pretty sharp feeling by the time I'm done. One week waiting for parts now. Maybe I'll start removing the old AOS.

I want to reiterate what I said previously and on the other clutch thread. If you have a 3.8 Stage 2 from Jake pushing out in excess of 350 to the wheels then I understand the need for the sports clutch and PP. But if you're driving or even racing a OEM 3.4 or 3.6 don't waste your money. The OEM replacement package from Sachs is much less expensive and all you'll need.....

I hear you JR, and you are not wrong...but follow my logic here: 1) My DMF has logged 190,000 km - it feels ok, but it's not ready for another 190K. A new DMF from Pelican is $900. 2) I have a LWFW coming for $525 - I've wanted a LWFW for a while anyway, and I save $375 - but even without the deal, a new LWFW is the same price as a DMF. 3) When using a LWFW - a spring centred clutch is a very good idea because at least there is *some* damping of the vibrations coming through the engine. Debatable whether this will save my crank but at least it will help with the transmission rattles. I may also get a better clutch feel. 4) At this point the OEM Sachs kit is a no go because it comes with a rigid disc. It's a great deal, but it can't be ordered with the spring centred disc. It costs $650. 5) Ordering the spring centred disc separately means you have to buy the pressure plate (and throw out bearing) separately as well. The difference between the cost of the sport PP and the OEM PP is about $200. Total cost for spring disc, throwout bearing and sport PP is $1200. Sustitute the stock PP and the price is reduced to $1000. Not a deal breaker, but that's the point where you are correct - I am probably spending $200 more than I need to. More importantly though I may be adding effort to my clutch pedal needlessly which is a concern because my hip is giving me trouble (hopefully temporary - the doc says I'm ok). So there you go. That's how I ended up with a sport clutch even though that was not my intention. It's all because of the LWFW...which I wanted for basically the right reasons. I'll post a review when it's all done - but this thread is for the rebuild project. Best

great post, keep up the good work! can't wait for more updates.

Clutch effort shouldn't change if you're using the factory pressure plate. You can install the RMS without any special tools, but why bother if it's not leaking. You said it was a recent motor, so it should have an updated seal. As for my 911, I pretty much rebuilt the engine in it. I'll post pics later if u guys want. I'll advertise it soon, I'm getting the itch for something faster (probably 996 turbo), but we'll see. Ok, I'll stop derailing your post. Good luck with your project.

You're not derailing we're just shooting the sh*t while I wait for parts. Question: What grease, if any, do you use on the guide tube?

Wheel bearing grease or axle/cv joint grease should be fine - though I believe most clutch kits may come with a bit of grease. You won't need much, just make sure everything moves smoothly. Here's a couple of my shenanigans, engine coming out: "Oil pan" area just before final re-assembly: I have to say even though I want something different and faster, I really enjoy this car. It sounds amazing (unlike my M3!) and is really a treat to drive/live with every day. 996 has to be one of my favorite platforms.

where are things at? parts in?

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last batch of parts arriving monday. These are the ones i need before I can do anything else though. I plan to replace the brake master and remove the AOS this weekend, work on the other its through the week, then re-install the transmission and button it all up next weekend.

OK! Parts are in and all accounted for so last night I installed the GBOX detent - not very exciting as far as the installation goes...mine came out with only a light amount of magnetic effort. Since the transmission is out it was genuinely simple. I can report however that the only difference between the stock detent and the GBOX piece is the diameter of the "wheel". Here's a photo of the two pieces, the GBOX part is on the right. Diameters of the wheels as measured: stock: 9.90 mm GBOX: 8.56 mm

Today I tackled the AOS replacement. This job has been described as one of, if not the most, unpleasant jobs on the 996 and despite a friend telling me that it's actually a "piece of ****" (that is to say easy) I have to say it was tricky to remove the old AOS *even with* the trans out and the motor dropped aaallll the way down. So low in fact that I wouldn't be able to re-install the transmission because of interference with the subframe. The two trickiest bits are the back mounting bolt which is blind as f*ck and in my case covered up by a bundle of wire, and I guess the top hose, which in the end actually was a piece of **** once I went at it from the engine compartment. The job took 3 hours of actual work...2.5 hours to remove the old part and 0.5 hours to install the new part. Two essential tools are the super long needle nose (pictured alongside my perfectly fine old AOS), and a 3/8 universal joint. Here's some snaps to make it a little more interesting: 1) Where I left off - all four wheel in the air. I can sit upright under the car with my head in the transmission tunnel...and I'm 6'0" 235 lbs. The four wheels are off because I replaced my brake master cylinder over the weekend and had to bleed all four corners. 2) Starting the job - remove the wire clip. 3) The first hose I removed let loose a bunch of coolant. Tip for the next guy: leave this hose till last. 4) I levered up the motor with a prybar and removed the hockey puck that was between the engine case and the top of the engine brace. Note that the bottom rim of the engine case is now below the subframe crossmember, which would prevent me from installing the trans if I left it. When the job was done I levered the motor up and reinstalled the hockey puck. 5) The massive hole from where I accessed the top hose of the AOS. 6) The perfectly fine AOS I removed, and one of the two tools I could not have done without. This AOS would probably go another 100K, but for $120 - it's cheap insurance. Note also that the AOS I removed (remember this is a 2005 M97 motor) had a part number ending in -050. The new part number ended in -051. They were visually almost, but not entirely, identical. The new part had an extra channel shaped support piece molded onto the top. Functionally I could not see why it would be there.

Well, that's a wrap. It all went back together this weekend and I don't know why, but it was about twice as easy putting it back together as it was taking it apart. The AASCO LWFW fit great, but the "torque ring" fit exactly one way only - see pics. If it was turned any one of the other eight ways, the holes didn't line up. I also took the time to fab up a flywheel lock according to peavynation's model from his watershed thread. Took an hour, but well worth the effort when it cam time to torque everthing together. I made mine out of steel, using a grinder to rough cut the teeth. Not pretty but it got the job done. In the end I did not replace the RMS. I tried to get a tool built, but struggled getting it square so I figured what the hell - it isn't leaking so let it be. If it starts to leak later, then I'll just drop the trans again and fix it then. It was not all that hard when all is said and done. What frankly amazed me was how easy it all came together. I slid the trans under the car, blocked it up on an ATV jack, strapped it down, hoisted it up, slid it towards the engine...lined it up...then I put a couple of bolts in, and it just sucked itself in from there. Done. Even the top bolt was a dawdle this time. I used about 4 feet of extensions, and did the whole thing from *above* the transmission. I can believe how hard it seemed on the way out and how easy it seemed on the way in. Don't even get me started on the slave cylinder...I just reached up and bolted it up. It wasn't even a bit difficult. Bizarre. Bleeding the new slave was a chore. Almost a full litre of ATE gold and the pedal still wouldn't come up by itself. It seemed to get better after a good shakedown run and a couple of pints though. I'm keeping an eye on this. Anyway - here's some shots of the flywheel job - I didn't get a lot of other pictures, things were moving pretty fast. My knees hurt, that's a drag. Driving impressions to follow:

Driving impressions: It's early yet but so far it's not the least bit harsh, which is not what I expected. Noise Harshness Vibration (NVH) from the RS motor mounts is not noticeable to me. It reacts more quickly to throttle inputs, but then again the LWFW will affect this. I can not find any reason to *not* install the RS motor mounts. LWFW - zippy throttle - check. Rattling from the gearbox - check. The noise doesn't bother me, but if I would not have been expecting it I would have been alarmed. Sounds like a diesel truck when I pull into my garage. Sport clutch - the pedal is light as a feather. I can feel the springs in the clutch disc working too. Overall a very pleasant thing to operate - notwithstanding the hydraulics issue which or the first few miles meant that the clutch pedal only came up halfway, just up to the fulcrum of the helper spring. This went away towards the end of my shakedown run. Just for kicks I put on my track wheels and tires too. All in all - it feels very sorted. Me likey!!