Simple Clutch terminology Question
Former Vendor
Joined: May 2005
Posts: 3,749
Likes: 4
From: Valencia Ca
Originally Posted by servohead
: Is a "PILOT bearing" the same as a "THROW OUT bearing" ?
Secondly, when we do clutches on a C5 do most kits come with a new flywheel?
Secondly, when we do clutches on a C5 do most kits come with a new flywheel?
The throw out bearing is located behind the clutch and its function is to press against the rotaing "fingers" and release the pressure plate.
In general, the flywheels supplied in a clutch kit are lighter, stronger, balanced etc., and in some way offer an advantage over the stock unit.
Burning Brakes
Joined: Aug 2004
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No, The pilot bearing is at the junction of the back of the crank shaft and the front of the transmission input shaft. The throwout bearing is the actuator assembly for the clutch. (aka slave cylinder) (c5=hydraulic) Replace both when doing a clutch job. I also recommend the LAPD remote bleeder for the slave cyl., and if you drive the car very hard it needs to be bled once a month to prevent the actuator from being damaged. The factory clutch kit comes with the flywheel, clutch disc, and pressure plate. Aftermarket kits vary. I replaced ours with all the Z06 parts. Hope this helps.
Race Director
Joined: May 2004
Posts: 16,667
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From: Raleigh, NC
St. Jude Donor '15
You said "no" then said the same thing Charlie said?? lol, wow
not true
if you drive the car very hard it needs to be bled once a month to prevent the actuator from being damaged
Burning Brakes
Joined: Aug 2004
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My no was in answer to his question,"Is the throwout bearing the same as the pilot bearing." I did not see the other post until I posted my reply. I base my info on the bleeder and using it monthly on my own experience. How do you figure it is not true?
Race Director
Joined: May 2004
Posts: 16,667
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From: Raleigh, NC
St. Jude Donor '15
i've never heard of anybody bleeding their clutch once a month and can't really mechanically think of any damage that would occur from not doing it. i agree on high HP cars its probably not a bad idea to keep the air out of the system if its becoming a problem...but I really have to wonder how any air can really get into the system to begin with if there are no other problems. do you notice any issues with your clutch when you're getting close to the one month mark or anythign??
Le Mans Master
Joined: Oct 2002
Posts: 6,772
Likes: 1
From: Tampa FL
Originally Posted by DRR
My no was in answer to his question,"Is the throwout bearing the same as the pilot bearing." I did not see the other post until I posted my reply. I base my info on the bleeder and using it monthly on my own experience. How do you figure it is not true?
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Former Vendor
Joined: May 2005
Posts: 3,749
Likes: 4
From: Valencia Ca
Originally Posted by DRR
No, The pilot bearing is at the junction of the back of the crank shaft and the front of the transmission input shaft. The throwout bearing is the actuator assembly for the clutch. (aka slave cylinder) (c5=hydraulic) Replace both when doing a clutch job. I also recommend the LAPD remote bleeder for the slave cyl., and if you drive the car very hard it needs to be bled once a month to prevent the actuator from being damaged. The factory clutch kit comes with the flywheel, clutch disc, and pressure plate. Aftermarket kits vary. I replaced ours with all the Z06 parts. Hope this helps.
The remote bleeder is good addition to any clutch swap (of course as the designer/originator of this little device, I am biased)
Charlie
Burning Brakes
Joined: Aug 2004
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I see no air getting in to the system per se. Clutch/brake fluid is very hygroscopic. (It pulls in moisture) This system on the C5 also gets very hot under hard driving conditions, and as this system cools down it draws in even more moisture. Water boils at a much lower temp than clutch/brake fluid. Ever look at a pan of boiling water? Where do the bubbles form? Part of maintainence is keeping things the same as they start out. Repair is fixing the damage that occurs when you fail to maintain something. To Charlie, thanks for making such a sweet part available.
Race Director
Joined: May 2004
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From: Raleigh, NC
St. Jude Donor '15
Do you mind explaining how exactly moisture from the air is going to get into the system, esp. around where all this change in temperature is taking place at the slave cylinder in particular...when it is all completely sealed off from the air? I can understand it getting into the fluid around the resevoir (although the rubber thing between the fluid and cap is suppose to help with this) but I have a hard time understanding how moisture could possibly get in any other way. I agree fluid should be replaced every so often, but every 30 days is just plain overkill to say the least IMO.
Burning Brakes
Joined: Aug 2004
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Don't mind at all, through heating and cooling. As the system heats, it expands or grows in volumne, displacing some of the air above the fluid. As it cools the fluid takes up less space and (even though it seems to be sealed) air returns to the space above the fluid. This is compounded by the fact that clutch/brake fluid is hygroscopic. It draws moisture form the air in contact with its surface. This air gets changed every time you heat and then cool the system. (Out goes the good air-ie dry, in comes the bad-ie wet) And, the hotter you get it, the more air you move in both directions. I assume you have a 6sp. Look at the master cyl. resevoir, see the air in there. We can't fill it to the top or it will puke or at least burp. Also, think again of my analogy of the boiling water, the bubbles form where the heat is introduced, at the bottom of the pan. In our clutch system the heat transfers from the p/p to the actuator bearing to the fluid. If you drive your car hard, then bleeding once a month is neither overkill or a waste of time. It is what I call maintainence. Now lets talk about that other system that uses a hygroscopic fluid- the brakes...Just kidding.
Race Director
Joined: May 2004
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From: Raleigh, NC
St. Jude Donor '15
There is a rubber piece that goes between the cap and fluid level in the clutch master cylinder. Its purpose is to move when the fluid level changes, be it for heating/cooling or natural wear/adjustment of the clutch, and is 'suppose' to prevent the air from actually being in contact with the hydraulic fluid thus preventing the transfer of water vapor in the air to the fluid. Regardless, there's no way fluid needs bleeding every 30 days...but it is a free country, have fun bleeding it if you so desire.
My car only has 180K on it though so I guess I wouldn't know much about long-term results of inadequate maintenance.
My car only has 180K on it though so I guess I wouldn't know much about long-term results of inadequate maintenance.
Burning Brakes
Joined: Aug 2004
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You don't say what car you have or if it is a 6sp. But if I may ask a couple of questions and you reply honestly, I would be able to tell if you drive your car as I said- very hard. Here goes-#1. With your 180k/mi, what have you replaced? #2. Have you ever broken anything, or just replaced things to maintain your car. #3. Do you ever drive it like you just stole it or been to a track of any sort? I must also tell you it is alot of work to drop the drive train, but very little to bleed the clutch. 15 min. tops. Pull up the ramp, roll under, a dab of lube on the end of the mity vac hose, stick it on the bleeder valve, pump it to ~28" vac and open the end of the bleeder until the fluid looks clean. I will understand if you don't want to answer any questions.
Race Director
Joined: May 2004
Posts: 16,667
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From: Raleigh, NC
St. Jude Donor '15
It is a 6spd and has been driven pretty hard on a regular basis...The clutch was replaced at around 90K and again around 160K which I think you will agree is pretty a pretty good lifespan for a hard driven C5. I have never really broken anything, the car is pretty much stock (heads/cam/headers are about to be installed) and until recently it was my only car so reliablity had to be first priority. I have no doubts you can bleed the system in around 15 minutes but that still does not justify doing so if it is not needed.
Again, I have no desire to argue with you on the subject, I was only trying to see if there was something I was missing and should be doing. I still do not think bleeding that often is necessary or even helpful but if you want to do it, by all means do.
Again, I have no desire to argue with you on the subject, I was only trying to see if there was something I was missing and should be doing. I still do not think bleeding that often is necessary or even helpful but if you want to do it, by all means do.
Burning Brakes
Joined: Aug 2004
Posts: 770
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You won't be able to bleed the clutch easily without a remote bleeder. Alot of work and very messy. Is your clutch fluid clear or a little (or alot) discolored? Our local Summertime temps peak above 110 degrees. For our car, I have found once a month bleeding keeps the fluid clear. This keeps the seal on the slave piston from deteriorating prematurely, causing slave failure. Props for getting 90k and then 70k on your clutches. You left some of my questions unanswered, but it sounds like you may in the future track your car, and at that time you may find what I have told you to be true. Thanks for chatting, and good luck with the h/c/h.
