Clutch question
03-19-2009, 08:11 PM
#1
Clutch question
Have any one of you Guys changed the clutch to your 996?. I got a divided opinion between 2 mechanics, one tell me that the flywheel can be machined & the other one told me, that flywheels are not machined that I need to buy a new one. Please advice.
03-19-2009, 11:07 PM
#2
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Normally, it is not necessary to replace the flywheel when you replace the clutch. There is no way a mechanic can be 100% certain that it needs replacing until he actually sees the condition of the flywheel once the clutch is removed.
03-19-2009, 11:21 PM
#3
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I also have heard both stories... if its bad replace it, and if its bad resurface it.... but these are special flywheels and I think there is some rubber involved so its not a "traditional" resurface.
Like Tim said there is no telling till it's in sight...
I helped do a clutch a few weeks back that went smooth...we just looked and the flywheel seems to be OK so we didnt touch it... its working perfect last I heard. My guess is that if it wear bad, we would have know by looking at it...
anyone have a picture of a bad one
Like Tim said there is no telling till it's in sight...
I helped do a clutch a few weeks back that went smooth...we just looked and the flywheel seems to be OK so we didnt touch it... its working perfect last I heard. My guess is that if it wear bad, we would have know by looking at it...
anyone have a picture of a bad one
03-19-2009, 11:36 PM
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As I asked in the previous thread, but was never answered...
What is the reason to replace a flywheel? What are you looking for on the flywheel (smear, uneven deposit?) and what is its effect?
In normal use, you are not removing flywheel material, only depositing clutch material on the face. Cleaning the surface with a flex-hone tool, Silicon carbide type abrasive, will removing insignificant amount of material and not affect the balance of a dual mass flywheel. Machining a flywheel is different than an abrasive scrub on the surface.
What is the reason to replace a flywheel? What are you looking for on the flywheel (smear, uneven deposit?) and what is its effect?
In normal use, you are not removing flywheel material, only depositing clutch material on the face. Cleaning the surface with a flex-hone tool, Silicon carbide type abrasive, will removing insignificant amount of material and not affect the balance of a dual mass flywheel. Machining a flywheel is different than an abrasive scrub on the surface.
03-19-2009, 11:40 PM
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If the clutch is slipping right now the flywheel is almost certainly bad now. The dual mass flywheels cannot be machined. Some people will say they can be turned and those people are most likely using an abrasive wheel on the mating surface. That WILL lead to clutch chatter if you do that, so don't.
If you never touch the flywheel you'll never know whether or not it's bad. If you grab it and twist it clockwise it'll spring back to it's normal position. A new one has very little travel, and you can tell a used one. A bad flywheel will not spring back and will usually travel further than a new one. A bad one will still work, and unless you drive enough of them, often enough it's hard to feel the difference.
If you have a bad flywheel then you need to replace it, that's it.
If you never touch the flywheel you'll never know whether or not it's bad. If you grab it and twist it clockwise it'll spring back to it's normal position. A new one has very little travel, and you can tell a used one. A bad flywheel will not spring back and will usually travel further than a new one. A bad one will still work, and unless you drive enough of them, often enough it's hard to feel the difference.
If you have a bad flywheel then you need to replace it, that's it.
03-19-2009, 11:44 PM
#6
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If the clutch is slipping right now the flywheel is almost certainly bad now. The dual mass flywheels cannot be machined. Some people will say they can be turned and those people are most likely using an abrasive wheel on the mating surface. That WILL lead to clutch chatter if you do that, so don't.
If you never touch the flywheel you'll never know whether or not it's bad. If you grab it and twist it clockwise it'll spring back to it's normal position. A new one has very little travel, and you can tell a used one. A bad flywheel will not spring back and will usually travel further than a new one. A bad one will still work, and unless you drive enough of them, often enough it's hard to feel the difference.
If you have a bad flywheel then you need to replace it, that's it.
If you never touch the flywheel you'll never know whether or not it's bad. If you grab it and twist it clockwise it'll spring back to it's normal position. A new one has very little travel, and you can tell a used one. A bad flywheel will not spring back and will usually travel further than a new one. A bad one will still work, and unless you drive enough of them, often enough it's hard to feel the difference.
If you have a bad flywheel then you need to replace it, that's it.
great info !
03-20-2009, 08:36 AM
#7
My car has 47000 miles, at this time my clutch doesn't slip or grab is only the sound that is making from the throw out bearing, just wanted an advise from the experts before going to the repair shop. Great advises all! 
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03-20-2009, 10:09 AM
#8
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So
you are having the clutch replaced because of a noise... suspecting the throw out bearing?
sure could be, but there are other noises that can replicate this and might NOT warrant a tranny R&R. What exactly are you chasing down, did the shop confirm it was the throw out bearing, what are the symtoms, when does it make them, does it ever not make them...
if nothing else it shoule help confirm your thoughts.
(also year - model) and if you get really bored I have an old thread where I was looking for a sqeal, there are good points and things to check. Mine went away after a tranny oil change?
LINK to thread
you are having the clutch replaced because of a noise... suspecting the throw out bearing?
sure could be, but there are other noises that can replicate this and might NOT warrant a tranny R&R. What exactly are you chasing down, did the shop confirm it was the throw out bearing, what are the symtoms, when does it make them, does it ever not make them...
if nothing else it shoule help confirm your thoughts.
(also year - model) and if you get really bored I have an old thread where I was looking for a sqeal, there are good points and things to check. Mine went away after a tranny oil change?
LINK to thread
03-20-2009, 01:21 PM
#9
First I noticed a squeak noise coming from the clutch pedal, when I pushed and release it, then I was told that there was also a thump noise coming from the engine compartment when I pushed the clutch, I was told by a mechanic that it was the throw out bearing the cause of the noise.
Either way I put silicon spray and later I used white lithium grease on the mechanism behind the pedal, but the squeak noise remained.
Either way I put silicon spray and later I used white lithium grease on the mechanism behind the pedal, but the squeak noise remained.
04-01-2009, 09:33 PM
#11
typicaly they will charge about 8 hours, I wouldnt think a throw out would cause a clunk or a squeak not that it isnt possible but maybe consider a second opinion.
You cannot machine the flywheel on a lathe, But we touch them up with a cookie wheel when we replace clutchs, 90% of the time the flywheel is ok.
If you drive the car till it stops moving, your gonna need a flywheel. And somes times the dual mass lets go and you get a rattle (think single mass) they tets this by twisting the fly wheel while bolted to the crank, if it doesnt return to center its bad.
You cannot machine the flywheel on a lathe, But we touch them up with a cookie wheel when we replace clutchs, 90% of the time the flywheel is ok.
If you drive the car till it stops moving, your gonna need a flywheel. And somes times the dual mass lets go and you get a rattle (think single mass) they tets this by twisting the fly wheel while bolted to the crank, if it doesnt return to center its bad.
04-01-2009, 09:39 PM
#12
Race Director
typicaly they will charge about 8 hours, I wouldnt think a throw out would cause a clunk or a squeak not that it isnt possible but maybe consider a second opinion.
You cannot machine the flywheel on a lathe, But we touch them up with a cookie wheel when we replace clutchs, 90% of the time the flywheel is ok.
If you drive the car till it stops moving, your gonna need a flywheel. And somes times the dual mass lets go and you get a rattle (think single mass) they tets this by twisting the fly wheel while bolted to the crank, if it doesnt return to center its bad.
You cannot machine the flywheel on a lathe, But we touch them up with a cookie wheel when we replace clutchs, 90% of the time the flywheel is ok.
If you drive the car till it stops moving, your gonna need a flywheel. And somes times the dual mass lets go and you get a rattle (think single mass) they tets this by twisting the fly wheel while bolted to the crank, if it doesnt return to center its bad.
04-01-2009, 10:09 PM
#13
Race Director
Dealer I checked with tech told me -- spoke to him right next to vehicle...
If the clutch is slipping right now the flywheel is almost certainly bad now. The dual mass flywheels cannot be machined. Some people will say they can be turned and those people are most likely using an abrasive wheel on the mating surface. That WILL lead to clutch chatter if you do that, so don't.
If you never touch the flywheel you'll never know whether or not it's bad. If you grab it and twist it clockwise it'll spring back to it's normal position. A new one has very little travel, and you can tell a used one. A bad flywheel will not spring back and will usually travel further than a new one. A bad one will still work, and unless you drive enough of them, often enough it's hard to feel the difference.
If you have a bad flywheel then you need to replace it, that's it.
If you never touch the flywheel you'll never know whether or not it's bad. If you grab it and twist it clockwise it'll spring back to it's normal position. A new one has very little travel, and you can tell a used one. A bad flywheel will not spring back and will usually travel further than a new one. A bad one will still work, and unless you drive enough of them, often enough it's hard to feel the difference.
If you have a bad flywheel then you need to replace it, that's it.
in for clutch -- worn right down to the rivets -- said common practice to send flywheels off for resurfacing.
If flywheel machined/surfaced once to provide true surface with acceptable finish it can be surfaced again if thick enough and if shop wants to go to trouble.
Sincerely,
Macster.
04-02-2009, 05:20 PM
#14
I just changed my clutch on my 03. The flywheel surface looked fine, but it had a pretty nasty amount of play, about 1/2" of both axial and radial play... it was totally shot. It had waaay more play than the new one I replaced it with, so, for peace of mind, I replaced it with a new one. I ended up spending about $800 on the new flywheel, which made the clutch job pretty pricey, but all the clunking noises went away.
