Why is my Clutch Trying To Explode?
08-11-2012, 03:11 AM
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Why is my Clutch Trying To Explode? Hey, so I undertook a slave cylinder/clutch replacement this last week, and once it was all back together it's trying to explode.
I took everything down to the pilot bearing apart, and installed a new: Pilot Bearing, (Resurfaced) Flywheel, CCI Stage 2 Clutch Disc and Pressure Plate. It took me a while to get the transmission lined up (several days). Once the car was sewn back together, I started it up and gave it a test 'go' in the driveway to ensure proper operation and shim size.
I revved it, and it shook a bit past 2000 RPM. I tried to engage the clutch, and it began to engage about 50% of the way up. About 75% of the way up, the car started shaking like it was going to destroy itself or blow something out the bottom. I never put it all the way to 100%.
So I'm terrified that I have messed something up royally. The obvious problems with such shaking is a) effed up the pilot bearing (shaking in 'gear'), or b) flywheel bad (shaking in neutral).
After total disassembly, the flywheel seems fine, except for a tiny 'chunk' missing (In the 1st photo, around the middle of the 9 o'clock area), which may have been before the refinishing, not sure. The pilot bearing seems fine. The clutch and clutch mating surfaces (pressure plate surface, flywheel surface) all share a small (1/4") contact patch around the area which doesn't exist across the rest of the surface. I know it won't be perfectly even as it wears in, but this thing seems like I'm going to explode my car!
So can anyone tell me what's wrong, or at least where to look? I've included photos of the Tranny spline for 'grease level' reference. Too little? Could too little grease be causing problem with the Pilot Bearing/Etc? Could my Pressure plate have been on unevenly? How important is it that all of the Plate's spring 'teeth' are even? Is that one small piece missing from the Flywheel a big deal? Should I be worried about the small (1/4") contact patch across the assembly? On the clutch disc, the non-flat part (in this case, shiny coppery side) should be facing towards the transmission, right? Might something else be wrong?
I took everything down to the pilot bearing apart, and installed a new: Pilot Bearing, (Resurfaced) Flywheel, CCI Stage 2 Clutch Disc and Pressure Plate. It took me a while to get the transmission lined up (several days). Once the car was sewn back together, I started it up and gave it a test 'go' in the driveway to ensure proper operation and shim size.
I revved it, and it shook a bit past 2000 RPM. I tried to engage the clutch, and it began to engage about 50% of the way up. About 75% of the way up, the car started shaking like it was going to destroy itself or blow something out the bottom. I never put it all the way to 100%.
So I'm terrified that I have messed something up royally. The obvious problems with such shaking is a) effed up the pilot bearing (shaking in 'gear'), or b) flywheel bad (shaking in neutral).
After total disassembly, the flywheel seems fine, except for a tiny 'chunk' missing (In the 1st photo, around the middle of the 9 o'clock area), which may have been before the refinishing, not sure. The pilot bearing seems fine. The clutch and clutch mating surfaces (pressure plate surface, flywheel surface) all share a small (1/4") contact patch around the area which doesn't exist across the rest of the surface. I know it won't be perfectly even as it wears in, but this thing seems like I'm going to explode my car!
So can anyone tell me what's wrong, or at least where to look? I've included photos of the Tranny spline for 'grease level' reference. Too little? Could too little grease be causing problem with the Pilot Bearing/Etc? Could my Pressure plate have been on unevenly? How important is it that all of the Plate's spring 'teeth' are even? Is that one small piece missing from the Flywheel a big deal? Should I be worried about the small (1/4") contact patch across the assembly? On the clutch disc, the non-flat part (in this case, shiny coppery side) should be facing towards the transmission, right? Might something else be wrong?
Last edited by Vyperion; 08-11-2012 at 10:17 AM.
08-12-2012, 02:25 AM
#2
The pilot bearing comes with grease on it. At least mine did. There is also a small seal so most of the grease you put on the point of the input shaft will get wiped off. Any grease on the input shaft can sling out and get all over the disk. I don't really have answers for any of your other questions. Sorry.
I was actually steered away from ARP flywheel bolts by a VERY reputable shop for the very reason that the lube needed to torque them down can ruin the clutch. They suggested that anything under 1000rwtq can use the GM TTY bolts without issue.
I was actually steered away from ARP flywheel bolts by a VERY reputable shop for the very reason that the lube needed to torque them down can ruin the clutch. They suggested that anything under 1000rwtq can use the GM TTY bolts without issue.
08-13-2012, 12:42 AM
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Well, every little bit of info goes towards a solution, so I appreciate it!
I was just reusing the stock bolts since they seem fine. Something that was mentioned elsewhere was that the clocking on the flywheel was wrong; I did not realize this mattered/was a thing, so there's at least that. When I put it back together again I'll try and find where it was originally.
One thing that I'm confused about is that several places/people mention 'indexing' of the flywheel and pressure plate. What does this mean/how do I do it?
I was just reusing the stock bolts since they seem fine. Something that was mentioned elsewhere was that the clocking on the flywheel was wrong; I did not realize this mattered/was a thing, so there's at least that. When I put it back together again I'll try and find where it was originally.
One thing that I'm confused about is that several places/people mention 'indexing' of the flywheel and pressure plate. What does this mean/how do I do it?
08-13-2012, 12:55 AM
#4
I think it refers to a clutch flywheel combo and that they are balanced together. They should stay aligned the same way. Or it refers to a flywheel with timing markings so it has to be oriented the same it was installed at the factory. We do not have to worry about that.
Also, do not reuse the stock GM flywheel bolts. They are torque to yield (TTY) meaning they are designed to stretch while being tightened. They are a one time use like the balancer bolt or stock head bolts.
Also, do not reuse the stock GM flywheel bolts. They are torque to yield (TTY) meaning they are designed to stretch while being tightened. They are a one time use like the balancer bolt or stock head bolts.
08-13-2012, 02:24 AM
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Ah, well then I'll have to get someone to drive me to the dealership (if they have some in stock). That's good info to have!
Do I need to have the whole assembly (flywheel, clutch disc, pressure plate) balanced together, or is that being excessive?
Do I need to have the whole assembly (flywheel, clutch disc, pressure plate) balanced together, or is that being excessive?
08-13-2012, 01:43 PM
#7
If the pressure-plate and flywheel were not balanced together then you could easily see vibration as a result of imbalance. As noted by Scooby, this disc may have a tendency to chatter to and this will be felt as the pedal is released and the clutch begins to engage. This is not balance related though, it is simply the nature of more aggressive disc materials.
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08-13-2012, 05:36 PM
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This is indeed my first time with a ceramic; I've been using the stock setup (car is just over 100k miles). Still seemed to be going ok, but since I had the whole thing apart for a Slave cylinder replacement, it seemed the time...
I understand that I should expect some chatter during break-in, and it won't be quite the same as the stock after which is fine. But I can't imagine this level of shaking is chatter - the whole car was shaking BADLY (to illustrate how bad, I'd say if it had been up on stands I have no doubt it would have shaken itself right off them), and never began moving while making bad sounds; I was letting it out really slowly since I didn't want the car to break if I screwed something up or to lurch into the garage.
I've received advice from several people in another thread about balancing the flywheel/PP together, but calling a local (highly regarded) transmission shop the guy had never heard of this; the only places he suggested was an Automotive Machine Shop nearby (who had recommended him) and a place that's pretty far away. I live in Dallas, TX so if it's important there must be someone around that does it... would a transmission shop be the place to look? How much should I expect to pay?
I understand that I should expect some chatter during break-in, and it won't be quite the same as the stock after which is fine. But I can't imagine this level of shaking is chatter - the whole car was shaking BADLY (to illustrate how bad, I'd say if it had been up on stands I have no doubt it would have shaken itself right off them), and never began moving while making bad sounds; I was letting it out really slowly since I didn't want the car to break if I screwed something up or to lurch into the garage.
I've received advice from several people in another thread about balancing the flywheel/PP together, but calling a local (highly regarded) transmission shop the guy had never heard of this; the only places he suggested was an Automotive Machine Shop nearby (who had recommended him) and a place that's pretty far away. I live in Dallas, TX so if it's important there must be someone around that does it... would a transmission shop be the place to look? How much should I expect to pay?
08-13-2012, 07:56 PM
#9
You definitely have a balance issue if its shaking that bad. But like stated above its not a good idea to grease the input shaft. Clean all that off before you put it back together.
08-14-2012, 09:59 AM
#10
You will need a facility with the ability to dynamic balance the parts. This is imperative for the LS based applications because the clutch and flywheel are not independently balanced during the manufacturing process. This means that when you separate the pressure-plate and flywheel and install a new plate on the same stock flywheel that re-balancing is required.
