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924/931/944/951/968 Forum Porsche 924, 924S, 931, 944, 944S, 944S2, 951, and 968 discussion, how-to guides, and technical help. (1976-1995)
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Old 09-22-2003, 10:44 AM
  #1  
TaboII
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Default Disaster

Failure Disaster!!!!

Clutch job in a weekend was in a word a failure, I spent three weekends on this as not to rush the job and in the end, well it is not functioning. I have spent several hours going over the steps and walking through each step of the process in my mind, I cannot think of anything that was don wrong!

Here is the symptom…

Car starts no trouble and sounds awesome thanks to new down pipes and a cat that doesn’t leak along with new gaskets from the headers back. Checking the clutch with the car still off the ground reveals nothing as it engages and sounds flawless “Which was very encouraging” Peddle movement and all looks feels as there is nothing that would indicate an incorrect or bad install. Depressing and releasing the clutches peddle is awesome and feels perfect, I even checked when under the car as Alos depressed and engaged the clutch. Absolutely nothing to worry about all looked and sounded great!

We put it on the ground and allow the car to warm in prep for a test drive. Alos “The owner” backs it out of the drive and we start off. First thing I notice is a serious shake as he attempts to release the clutch in first gear. Once engaged all seems fine until second gear. Same thing, Chatters and shakes as the clutches peddle is released but once in gear it operates correctly, and feels solid acceleration is normal and deceleration is normal. No slipping at all is recognizable and I don’t feel any real abnormal vibrations.

During the process of the clutch job we checked and rechecked every step replaced any incorrect bolts with new and check torque setting along the way. We took the extra time on this job just to ensure there would be no problems when complete and now this..

I can’t believe we don’t have a perfectly operating car.

Now I completely understand how a clutch works as this is not the only clutch I have installed in my life. Everything during the install was checked and rechecked to prevent this sort of thing from happening in the first place and NOTHING seemed out of the ordinary.

I drove the car and can feel the grab and release of the clutch in the bell housing. Once engaged it seems fine however getting it to engage smoothly is not possible. From my own experience with clutch installs this feel like a broken clutch or a badly warped pressure plate or fly wheel. Now the clutch is new along with the pressure plate and through out bearing, everything looked perfect and flawless. Even the bearing guide is new and the torque is correct on all installed pieces. I visually inspected everything before assembly very carefully and found nothing wrong or alarming. Installation was a breeze and well received. There where no troubles to speak of that I can even remotely remember.

My personal thinking is that the fly wheel is some how warped in some way causing the chatter/shaking during the time of engagement to be so strong and without getting into details I would like all of your trouble shooting thoughts and or possibilities. We or should I say “I” need to see if this cannot be corrected soon. And may be looking for some assistance as I have to find out what the problem is and soon.

Comments please, questions and or suggestions, ANYTHING, I need to determine what when wrong and soon. It’s going to get cold up here very soon and I need to get this car completed before then.

HEEEELPPPP please anybody?

TaboII
Old 09-22-2003, 11:05 AM
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Jon Moeller
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Really stupid question from a newbie, but could you have gotten some lubricant on the clutch surface? Does the clutch need to bedded in?

My only clutch job was on a BMW, and everything was smooth, right out of the box. I know the work involved with that, and hope that there's an easy answer.
-J
Old 09-22-2003, 11:07 AM
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markford944
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A warped flywheel, defective parts, or possibly the clutch not being centered exactly right are a few possibilities; sort of doesn't matter to speculate, however, unfortunately you are going to have to tear it all apart to figure it out....good luck MF
Old 09-22-2003, 11:11 AM
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billybones
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If you did not have the flywheel turned. Did you at least break down the surface of the flywheel by sanding it? You have to breakdown the imbeded left overs from the last clutch.. If you don't you will have to basically burn it out with the new clutch.(reduces life expectancy). sorry but that is the price for not having it turned. Or sanding the living daylights out of it. I sanded mine and it still took like 3 weeks to get rid of the chatter.. someone here once wrote that if you take it to a steep hill and half feather it up the hill (creating a lot of friction) a few times. You could set the new clutch.. in less time... From what you wrote that would be my guess is that the clutch needs to be set.. given enough time in regular driving it will eventually get there.. but the clutch will not live as long as it should have... ie 3 years instead of 5. HTH..
Old 09-22-2003, 11:34 AM
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TaboII
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TaboII

Ok you guys seem to be going that same place I did during my mental walk through of the job.

1) New bee questions are allowed here and actually that was a good question. There was NO oil or derbies on the flywheel clutch surface I was very careful to ensure that this was the case.

2) I used the fly wheel clutch alignment tool during the install and double checked that it was in place correctly before locking downs the pressure plate bolts. I only remove the clutch alignment tool AFTER the pressure plate was installed and all bolts torqued down and double checked. It came out with little to no trouble which was what I was looking for just for the purpose of alignment. BTW the Torque tube slid right in with little to no effort reassuring me that the alignment was dead on.

3) OK to the fly wheel. This is the part that I intentionally left out of my original post and was hoping one of you could reinforce. The fly wheel was resurfaced by a machine shop. I did not question the surfacing as I was told that this was an awesome place. Now, I had noticed something on the fly wheel that alarmed me the first time I saw it. On the inner side if the fly wheel lip “not on the mating surface” there was a large mark that ran half the circumference of the whole fly wheel and I could tell that this was done at the same time as the surfacing. It was suggested that it was balancing that was necessary so I dismissed it as truth and when on with the job. I am now calling this into question and dreading the consequences of the suggestion in hindsight.

4) As far a seating the fly wheel/clutch. I do not think that this is the case; I mean we are not talking about a ford here. The tolerances are two tight so much so that I would think if I tried to burn or seat the clutch in I would destroy the clutch in the process. But thank you for the suggestions and please don’t hesitate to suggest things like this, who knows I have seen similar problems like this solved by the simpler suggestions

Thanks so far guys keep them coming.

TaboII
Old 09-22-2003, 11:41 AM
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markford944
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Bottom line to me is that, unless your problems somehow spontaneously disappear, I would be afraid of chewing up expensive parts in trying to operate the car with it functioning as you describe - you'll need to tear it down to inspect the parts. Anything else is just speculation. I doubt there's much of anything you can do without a teardown, as you know the hydraulics are about the only easily accessed parts of the clutch system. MF
Old 09-22-2003, 11:45 AM
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TaboII
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MF944,

As much as i hate to admit your right, I know you are. Three weekends down the tubes!!!

* Sitting with elbows now on knees hands supporting my head in pathetic defeat*
Old 09-22-2003, 12:01 PM
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markford944
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Yeah, bro, I feel for you - BTDT many times on these cars with only the details changing...
Old 09-22-2003, 12:24 PM
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marky522
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Did you replace the pilot bearing??? I chased this EXACT problem in my 924, if you think about it it makes sence, the pilot bearing keeps the "driveshaft" in the Torque Tube centered when the clutch isnt engaged and holding it, all that chatter and shimmy is the clutch spinning out of round, no one had ever heard of this when it was my problem and it ended up costing me 3 clutchs and countless hours, i can now do a clutch in about 4-5 hours on the ground... Sorry to hear your misfortune...


Mark
Old 09-22-2003, 12:28 PM
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Bryan
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Some questions:

- Did you check that the release bearing was still snug on the radial pressure plate springs after you bolted the pressure plate up to the flywheel? Installing the release bearing on the pressure plate is NOT intuitive. When not bolted to the flywheel, the radial pressure plate springs are at a slight angle. So when you install the release bearing, it feels snug. But when you install it on the flywheel, the pressure plate compresses and the radial springs flatten out. This can make the release bearing loose.

My release bearing came with no instructions but several round shims. These shims are for making the bearing fit snugly.

- As you bolt the pressure plate to the flywheel, there are flat springs around the outer edge of the pressure plate which compress as the bolts tighten. Are you 100% sure all these bolts went in all the way and pulled the pressure plate uniformly to the flywheel?

- Did you use a spring center or rubber center disk? The spring center disk is marked which side goes against the engine and which goes toward the gearbox (getrieb). Are you sure the disk is facing the right way?

- Did you mess with your clutch fork at all? A new fork is well over $200, so I doubt you replaced it (I almost fell out of my chair at the price and elected not to replace mine either). I did do new roller bearings and (long story) found a nice smooth pivot shaft (not chewed up by the old roller bearings). I also re-shaped my clutch fork where it touches the release bearing. I Dremeled curvature back into it so it meets the release bearing nice and square and can rock smoothly.

- Where in the pedal travel does the clutch start to grab? Mine is toward the top of the travel - with the pedal about halfway up. It shouldn't grab right off the floor.

- Ignoring the shaking, does the car shift OK? No grinding of gears or hard to get into/out of gear?

We'll figure this out...

Bryan
Old 09-22-2003, 12:33 PM
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Default Pilot bearing

Marky522

Yes I thought about this as well and at the same time I replaced the rear main seal. It went in perfect, both the bearing and the seal. Again the TT seated completely in the housing with no trouble at all, it just slipped right in. If there was a hang up on the Pilot Bearing it would not have seated at all. BTW after the clutch is engaged all operations seem normal. It is only engaging the clutch when feathering it so to speak that the chatter occurs. I would think that if the pilot bearing was missed and the TT was not resting in its proper place there would be a hell of a lot more vibrations after the clutch is engaged , wouldn’t there?
Old 09-22-2003, 12:36 PM
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GTZ
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I just went through the exact same thing on mine. As it turned out, I had the wrong clutch. The company I bought mine from obviously cobbled something together, but it wasn't the correct height clutch.
Sachs had a new part number for the clutch and PP. The older model had a short snout on the clutch plate that casusd it to be at the very end of the travel. The updared part has a longer snout that is the same height as the rubber center clutch.
I just put a new updated part in mine, and it is a night and day difference.
If you bought it from Vertex, it's probably the wrong one.

Here's Sachs part numbers. Double check that you have the correct ones

http://webcat.sachs.de/

Randy
Old 09-22-2003, 12:48 PM
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marky522
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TaboII, With my car, when i had the problem with my pilot bearing, the only time i ever had a problem wa swhen i would use the clutch, when it was in gear it was fine, i drove it down the h-way at 85MPH and didnt have a problem till i had to shift. Yours is a NA correct??? If so IF i can find it I will send you a pilot bearing, when i ordered the one for my 924, they send me the one for the 924S which i do believe is the one for you. Your going to have to pull it apart anyway, you can put this in there Just in case, i really ont want you to have to go through the hell that i did.

Mark
Old 09-22-2003, 01:07 PM
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TaboII
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Unhappy Answers

Bryan

Question: Did you check that the release bearing was still snug on the radial pressure plate springs after you bolted the pressure plate up to the flywheel?

Answer: Yes as I followed the factory manuals, hayes “Excuse the spelling” and a walk through printed from two separate websites just to make sure I have enough information. I check this physically with my finger and visually. It was snig and right on the money. The shims where something I paid close attention to because of this possible problem

Question: Are you 100% sure all these bolts went in all the way and pulled the pressure plate uniformly to the flywheel?

As I did not try and assemble the outer casing at the same time as some suggested I had a clear and unobstructed view of the pressure plate. I actually star patterned the Allen bots twice, fist at the recommended NM don’t remember at the moment what that was and then checked the torque setting and re-followed the procedure again to ensure they where all correct. I also followed this same procedure for installing the fly wheel. I am 99.9 % sure that everything was perfect as I lay there for several minutes checking out all the springs and plate to make sure I wasn’t missing anything and all looked good.

Question: Did you use a spring center or rubber center disk? The spring center disk is marked which side goes against the engine and which goes toward the gearbox. Yes if you look at the Sachs clutch there is actually only one way it can go in and fit correctly. OK Well I suppose if one was not to savvy there could be a possibility that it could be put in the wrong way, but I have to say that once the system is engaged all feels good with no clipping or excess vibrations.

Question: Did you mess with your clutch fork at all?

Answer: Yes, though I did not round out the ends of the mating surface as you did, we did replace the bearings and put in a new pivot shaft. All of which went together flawlessly, oh I also lightly greases the fork ends as the factory manual suggested. I am again 99.9% sure that this was put together correctly and was operating correctly. I viewed it releasing and engaging the clutch from under the car through the plug hole. It looked awesome and correct as it could have.

Question: Where in the pedal travel does the clutch start to grab?

Answer: Right near the top of the travel during release as it should. In fact there is no abnormal clutch feel at all. I was expecting a nice even grab to occur all at once. Instead I get this almost violent shaking if I give it any RPM’s and then it will finally starts to grab a bit and move the car forward. Again once engaged the car will accelerate and decelerate with no slipping or abnormal vibration. Basically when it grabs it is even or at least centered enough not to cause vibrations, off axis any way. It is a first for me. Usually the problem is something was off center. Or as plane as a busted plate or clutch the way this thing jumped around. I am confused to say the least here.

Question: Ignoring the shaking, does the car shift OK?

Answer: Yes perfectly aside from the shaking if there is any feathering of the clutch at all. If I RPM shift I do not experience the shaking/vibration and all gears function perfectly. There I what sounds like input shaft bearing noise on the transmission but this vibration would not be cause by this. This is a fact not a guess. I may be replacing the transmission seals, drain plug and possibly the input shaft bearing while I am in there as they are not expensive items. BTW we jet washed off the transmission so the noise we are hearing now may be a result of washing of all the noise damping grease that had built up on the tranny. I am not actually worried about it as right now there are bigger problems to correct. I think you all would agree.

Bryan I appreciate the confidence and assistance. It is needed. I hope the answers are clear enough.

TaboII
Old 09-22-2003, 01:20 PM
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Default OMG

GTZ


PLEASE TELL ME YOU TELLING ME A STORY TO MAKE ME FEEL BETTER.
WE DID BUY THIS FROM VERITEX!!!!!!

Now that you mention this I do remember thinking to my self that it was a bit odd that it was a differnet thickness but dismissed this thinkign hey this came in a kit all together it had to be right.

I HOPE THIS IS NOT THE CASE!!

I am going to call and get the part number off the kit now from Also do you still have the partnumbers for the right and wrong parts?

this might make sence!


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