Clutch question
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Advanced
Joined: Dec 2014
Posts: 64
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From: CT
Clutch question
I have about 850 miles on the car, and the clutch engages very high up - it feels like there is very little clutch there, but there's no way it's been worn down in 850 miles. I can't say if it feels different from day 1; I don't think so.
It's been a very long time since I've owned a manual. Are all of yours like this as well?
Thank you.
Seth
It's been a very long time since I've owned a manual. Are all of yours like this as well?
Thank you.
Seth
Racer
Joined: Dec 2009
Posts: 356
Likes: 23
From: Augusta Georgia
Do change clutch fluid with GM super dot 4 often. The C7 is no different than the C6 clutch reservoir. Fluid will get dirty. I suctioned and replaced my fluid at 500 miles and will do so continuously. New clutch means the whole drivetrain must be removed, and even under warranty, I'll pass.
Burning Brakes
Joined: Sep 2014
Posts: 1,130
Likes: 49
There is no reason to change the fluid every 500 miles. Maybe 5000 if you beat on your car. Its really just brake fluid, you wouldn't change that every 500 miles. its only used to "push" not lubricate so it wont get dirty fast like engine oil
Race Director
Joined: Jul 2007
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From: Texas Hill Country
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Melting Slicks
Joined: Oct 2007
Posts: 2,398
Likes: 858
If I recall from the early C5 days they had some clutch slave cylinders and master cylinders fail prematurely. It was suspected by some that debris in the clutch fluid from normal slave and master seal wear and corrosion was causing more wear and tear on the slave and master seals.
In other words the fluid got more abrasive as the seals wore and the vicious circle continued until one of the cylinders failed from eaten up seals. You will notice the fluid color change from clear to the dark brownish over a fairly short time. Some of this is normal due to heat cycling of the fluid but some is also from debris.
I think this problem was solved circa 2000ish.
However the fluid still turns brown. And the seals still wear. It’s just part of the design. But “NOW” this normal process has been addressed in the seal design.
I am sure if folks change the fluid often they will get some benefit from it down the road. So that’s cool. The idea is to make it the point where you have to change the clutch disc before the slave cylinder fails since it requires the same amount of work to replace either. This can probably be reached by just following GM’s recommended change interval. A few extra changes may tilt the odds further in your favor.
Last edited by dar02081961; Feb 19, 2015 at 05:50 PM.
Pro
Joined: Nov 2010
Posts: 600
Likes: 29
From: Tampa Florida
Jd; I think he means the fluid isn’t clean.
If I recall from the early C5 days they had some clutch slave cylinders and master cylinders fail prematurely. It was suspected by some that debris in the clutch fluid from normal slave and master seal wear and corrosion was causing more wear and tear on the slave and master seals.
In other words the fluid got more abrasive as the seals wore and the vicious circle continued until one of the cylinders failed from eaten up seals. You will notice the fluid color change from clear to the dark brownish over a fairly short time. Some of this is normal due to heat cycling of the fluid but some is also from debris.
I think this problem was solved circa 2000ish.
However the fluid still turns brown. And the seals still wear. It’s just part of the design. But “NOW” this normal process has been addressed in the seal design.
I am sure if folks change the fluid often they will get some benefit from it down the road. So that’s cool. The idea is to make it the point where you have to change the clutch disc before the slave cylinder fails since it requires the same amount of work to replace either. This can probably be reached by just following GM’s recommended change interval. A few extra changes may tilt the odds further in your favor.
If I recall from the early C5 days they had some clutch slave cylinders and master cylinders fail prematurely. It was suspected by some that debris in the clutch fluid from normal slave and master seal wear and corrosion was causing more wear and tear on the slave and master seals.
In other words the fluid got more abrasive as the seals wore and the vicious circle continued until one of the cylinders failed from eaten up seals. You will notice the fluid color change from clear to the dark brownish over a fairly short time. Some of this is normal due to heat cycling of the fluid but some is also from debris.
I think this problem was solved circa 2000ish.
However the fluid still turns brown. And the seals still wear. It’s just part of the design. But “NOW” this normal process has been addressed in the seal design.
I am sure if folks change the fluid often they will get some benefit from it down the road. So that’s cool. The idea is to make it the point where you have to change the clutch disc before the slave cylinder fails since it requires the same amount of work to replace either. This can probably be reached by just following GM’s recommended change interval. A few extra changes may tilt the odds further in your favor.
Last edited by Cyclone09Z06; Feb 19, 2015 at 09:09 PM.
Race Director
Joined: Dec 2006
Posts: 12,393
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From: Fort Worth, Texas
Starting with the c6 in '05 a rubber boot/sleeve was added around the spring that keeps the release bearing against the diaphragm springs to try and cut down on the dust that gets past the seal on the slave cylinder as it's actuated. It may help, but dust still gets past it as it's not air tight. So I agree that swapping the clutch fluid in the clutch master cylinder reservoir, but that's only diluting things as the fluid nearest the slave is dirtiest. Bleeding it at the bleeder valve is best, but having a remote bleeder makes it easier to do.
Last edited by PRE-Z06; Feb 19, 2015 at 10:09 PM.
Le Mans Master
Joined: Oct 2004
Posts: 6,813
Likes: 287
From: Toronto Ontario Canada
Those that understand how hydraulic systems work will realize that changing the fluid in your reservoir with the Ranger method has minimal effect on what happens in the clutch system. It is a cosmetic change more than anything and does nothing to remove sludge in the slave.
Last edited by b4i4getit; Feb 20, 2015 at 08:35 AM.
Race Director
Joined: Jul 2007
Posts: 10,961
Likes: 2,643
From: Texas Hill Country
Those that understand how hydraulic systems work will realize that changing the fluid in your reservoit with the Ranger method has minimal effect on what happens in the clutch system. It is a cosmetic change more than anything and does nothing to remove sludge in the slave.
Le Mans Master
Joined: Oct 2004
Posts: 6,813
Likes: 287
From: Toronto Ontario Canada
There are some that have the idea that doing the Ranger method often is just as good as a complete system bleed. This is simply not true because sludge is heavier than fluid and will stay down in the slave causing problems. GM should really do us all a favour and install a remote bleeder as factory equipment.
Melting Slicks
Joined: Nov 2005
Posts: 2,074
Likes: 309
I don't think the problem was solved with the C6, either, and my Z28 had the same problem. Changing the fluid frequently is far less of a hassle than dropping the exhaust and entire drive train to replace the clutch slave cylinder, if changing the master doesn't do it. Given how similar the C7 is to the C5 and C6, I would predict the same problem, unfortunately.