: Clutch reservoir low fluid level?



SFBayV
10-28-08, 10:06 AM
Good morning gang.

Along with other clutch related issues, I've had a reservoir which was empty. Upon my dealer looking at the car, the service adviser said that he'd remembered a bulletin stating that a low fluid level condition was the result clutch wear and was normal. I've looked at the FAQ and haven't been able to find this bulletin.

My question is this. Wouldn't normal clutch wear require less fluid? I say this because as a clutch wears, it gets thinner. Therefore the pressure plate requires less movement in order to disengage the clutch disc. Wouldn't this wear also cause the fingers of the pressure plate to move closer to the throwout bearing? If this is correct, what would cause a low fluid level condition other than a leak? Thanks all.

Cory

nmaier2201
10-28-08, 11:22 AM
what did you put in it to fill er back up?

ctsv154
10-28-08, 11:27 AM
As the clutch wears, the plate does get thin. Which means the piston in the slave has also moved out farther which will require more fluid to fill the void behind the piston. In other words. The clutch wears, you add fluid.

JonCR96Z
10-28-08, 11:32 AM
Good morning gang.

Along with other clutch related issues, I've had a reservoir which was empty. Upon my dealer looking at the car, the service adviser said that he'd remembered a bulletin stating that a low fluid level condition was the result clutch wear and was normal. I've looked at the FAQ and haven't been able to find this bulletin.

My question is this. Wouldn't normal clutch wear require less fluid? I say this because as a clutch wears, it gets thinner. Therefore the pressure plate requires less movement in order to disengage the clutch disc. Wouldn't this wear also cause the fingers of the pressure plate to move closer to the throwout bearing? If this is correct, what would cause a low fluid level condition other than a leak? Thanks all.

Cory

I think your dealer meant that its normal that the fluid drops with wear on these cars. Mine started acting weird and I checked the fluid. It was gone. Topped ti off and flushed the fluid and it acted normal again. Changed the clutch about a month later (which isn't many miles for me) and the stock one was about as completely done. Since your having troubles you may want to go ahead and set aside some money for a clutch, just to be on the safe side.

The disc gets thinner so the fluid stay in the slave cylinder taking up the slack. The TO bearing always touches the fingers on the PP that's the design.

SFBayV
10-28-08, 11:46 AM
As the clutch wears, the plate does get thin. Which means the piston in the slave has also moved out farther which will require more fluid to fill the void behind the piston. In other words. The clutch wears, you add fluid.

That's my question. Why would the piston have moved out farther? Since the disc is thinner, the fingers of the clutch would be closer to the TOB as opposed to being farther away. I'd think that this would require less fluid as the wear gets worse.

Would anyone have a diagram or any exploded views of the TOB and slave?

SFBayV
10-28-08, 11:47 AM
what did you put in it to fill er back up?

I used DOT 3 brake fluid to replace the expended fluid. I "believe" that is the recommended fluid to use.

ROG
10-28-08, 11:52 AM
I know the 06 V says use DOT 4.

JonCR96Z
10-28-08, 12:23 PM
The TO bearing always touches the fingers on the PP that's the design.


That's my question. Why would the piston have moved out farther? Since the disc is thinner, the fingers of the clutch would be closer to the TOB as opposed to being farther away. I'd think that this would require less fluid as the wear gets worse.

Would anyone have a diagram or any exploded views of the TOB and slave?

Now that I think about it where does the fluid go? Since pushing the fingers forward releases tension on the disc, it looks like a worn disc would allow the fingers to go back farther than normal. Actually causing less fluid to be held in the slave? Unless the spring tension of the fingers goes away as well.

SFBayV
10-28-08, 12:55 PM
Now that I think about it where does the fluid go? Since pushing the fingers forward releases tension on the disc, it looks like a worn disc would allow the fingers to go back farther than normal. Actually causing less fluid to be held in the slave? Unless the spring tension of the fingers goes away as well.

Exactly. The pressure plate converts the forward movement of the throwout bearing into the rearward motion of the plate itself. So, as the disc wears over time, the less rearward movement of the plate is required since the pressure plate doesn't have to move as far to release the disc. So, when the reservoir is empty, where does the fluid go?

Cory

stuckey
10-28-08, 05:35 PM
All the V's 04-07 use DOT4 its basically a synthetic version of DOT3 as far as I know.

PISNUOFF
10-28-08, 05:50 PM
Would anyone have a diagram or any exploded views of the TOB and slave?

The TOB is part of the Slave.

Stoopalini
10-28-08, 05:52 PM
All the V's 04-07 use DOT4 its basically a synthetic version of DOT3 as far as I know.

I thought DOT 4 was just rated for higher temps than DOT 3 and DOT 5 was the synthetic?

Thomas.

SFBayV
10-28-08, 05:57 PM
All the V's 04-07 use DOT4 its basically a synthetic version of DOT3 as far as I know.

I don't have my manual with me, but I think that DOT 3 was used in 04-06 models.

atdeneve
10-28-08, 06:00 PM
I thought DOT 4 was just rated for higher temps than DOT 3 and DOT 5 was the synthetic?

Thomas.

Yes.


I don't have my manual with me, but I think that DOT 3 was used in 04-06 models.

And yes.

stuckey
10-28-08, 06:05 PM
Thanks for correcting me! I was encouraged to replace mine with DOT4 when I bled it all off and changed fluids. Did this for the brakes as well.

SFBayV
10-28-08, 06:05 PM
The TOB is part of the Slave.

PISNUOFF, thank you very much for the illustration.

This appears to support what I'm thinking. The further the TOB has to move into the pressure plate, the more fluid is required. As the clutch disc wears, less fluid is required to disengage the disc. So, over time the fluid level should not go down. With that said, other than a leak, where would the fluid be going?

I've just spoken with the dealer and they've said that they'll look up the bulletin which states that as the disc wears, the fluid level goes down.

Thank you to everyone for all of your input.

Cory

gauge hp
10-31-08, 01:35 PM
PISNUOFF, thank you very much for the illustration.

This appears to support what I'm thinking. The further the TOB has to move into the pressure plate, the more fluid is required. As the clutch disc wears, less fluid is required to disengage the disc. So, over time the fluid level should not go down. With that said, other than a leak, where would the fluid be going?

I've just spoken with the dealer and they've said that they'll look up the bulletin which states that as the disc wears, the fluid level goes down.

Thank you to everyone for all of your input.

Cory

You could have a leaky slave cylinder, happened to me progressively got worse you don't see the fluid on the ground at first because it tends to lay in the bell housing. the fluid will ruin your plates if it gets bad enough.

ROG
10-31-08, 01:46 PM
It was my Cadillac sevice manager that told me that only DOT4 was to be used in the V. He was going to top mine off but they didn't have any! LOL

Bueller
10-31-08, 02:55 PM
http://www.stoptech.com/tech_info/wp_brakefluid_1a.shtml

I just replaced my clutch fluid and did a full brake bleed with Motul RBF660. Expensive but Wow what a difference. I only had 10,000 miles on the stock fluids.

Dot 3 and 4 and 5.1 are compatible and all Glycol Ether based. They are water soluble so try not to keep the res open long. I even close the cap on the bottle right away. It will absorb humidity from the air and reduce the boiling point.

Dot 5 is Silicone based and should NEVER BE USED. It is compressable and will not mix with the others. It will ruin and swell any rubber that was in the system. Don't use Dot 5!

nmaier2201
10-31-08, 03:01 PM
Thanks Bueller, that article was pretty good.

RGRATTAN
10-31-08, 07:52 PM
You could have a leaky slave cylinder, happened to me progressively got worse you don't see the fluid on the ground at first because it tends to lay in the bell housing. the fluid will ruin your plates if it gets bad enough.

You deff have a leaky slave the guy at the dealer is either a tard or is just trying to get you out of there.

When the clutch disc and pressure plate wear in the V (just like all single disc setups in any car Vett, Honda, whatever) they only lose a few thousandths thickness and this will not contribute to the clutch slave fluid level lowering on any car.

Sorry my bench racing friends but there is not enough meat on a single disc clutch setup to do that.

Take you car to the dealer and break out the manual in front of the idiot that was helping you last time. It basically says the fluid is good for the life of the car and if it is low or empty take the car to the dealer immediately.

My car is suffering the same fate our hydro throw our bearing is a POS and is leaking the bad part is that it is leaking on the clutch itself and will deff shorten the life of your clutch if not ruining it all together. I've felt my clutch developing hot spots lately and I feel a total replacement under warranty coming soon.

If you guys look there have been people who have replaced our POS throwouts with a Corvette one with some mods (of course)

ewill3rd
11-01-08, 07:36 AM
The clutch fluid doesn't drop as the disc "wears".
Unless you are abusing it the clutch really doesn't wear in a measurable sense and if it does you don't know how to drive a stick.

The fluid does go down, it turns black, it will even gel up if you ignore it.
I have seen this a lot and I think that temperature combined with component composition just wears the fluid out.
I have yet to see one of these systems leaking anywhere, at first I was confused by the apparent fluid loss, then I realized that something about the system just breaks the fluid down and makes it do this... don't ask me for a scientific definition, I can't give you one. All I can say is check your fluid, when it turns black change it out and flush the clutch hydraulic circuit and you won't believe the difference. This appears to be a badly overlooked maintenance item and we may see more of them than any other dealer I have heard of.
The manual calls for a DOT 3 fluid, GM actually makes a dedicated DOT 3 clutch fluid, but brake fluid will do.
A lot of guys have opted for DOT 4 but we haven't seen whether or not it is prone to the same issues.

darkman
11-01-08, 07:57 AM
I've just spoken with the dealer and they've said that they'll look up the bulletin which states that as the disc wears, the fluid level goes down.


I subscribe to the 2005 V technical bulletins and there is no such bulletin in my set.

ewill3rd
11-01-08, 08:55 AM
I have access to the same information that they do, there is no bulletin that indicates an issue of that nature.

C66 Racing
11-01-08, 01:47 PM
Not trying to hijack the thread, but adding some clarification to points made above. In general, most DOT 3 and DOT 4 and DOT 5.1 fluids are polyglycol ether-based and are compatible with each other. DOT 5 is silicone based and is not compatible with other brake fluids.

DOT 3, 4 and 5.1 polyglycol ether-based fluids are hygroscopic, which means they absorb water easily and hold it in suspension, similar to antifreeze. In most climates, moisture seeps into the brake system continuously through the various seals and microscopic pores of the flexible brake lines. This seepage can accelerate as a vehicle ages and theres almost no limit to how much water the fluid can absorb. By the time brake fluid has been in the system for three years, it can easily reach its wet boiling point. Because this happens gradually, most drivers wont discover the reduced boiling point.

DOT 5 silicone based fluids are not hygroscopic, however this means that instead of being dissolved, any water in the system will eventually find its way to the lowest point in the brake line, corroding it, and potentially boiling and causing brake failure.

The primary difference between a DOT 3 and DOT 4 is its minimum wet and dry boiling points. The minimum dry boiling point for DOT 3 brake fluid is no less than 205C (401F), and the minimum wet boiling point is 140C (284F). That might not seem very high, but in most brake systems (and likely clutch systems), the fluid in the caliper wont reach that temperature unless the brakes are abused. It only takes four percent water contamination to bring a DOT 3 fluids boiling point down to the federal limit.

The minimum dry boiling point for DOT 4 brake fluid is 230C (446F), while the minimum wet boiling point is 155C (311F). Their higher boiling points make DOT 4 fluids appropriate for high-performance cars.

Note that all of these are minimums. For an alternative to foreign brake fluids such as Motul (which is a good fluid), AMSOIL now makes both DOT3 and DOT4 fluids that far exceed the mininum specs. I run the DOT4 in my track day 02 Corvette Z06.

AMSOIL Series 500 High Performance DOT 3 Brake Fluid (http://www.c66racing-synthetics.com/Specialty%20Products/BF3PB.htm)
Dry 274C (525F), wet 156C (313F).
AMSOIL Series 600 DOT 4 Racing Brake Fluid (http://www.c66racing-synthetics.com/Specialty%20Products/BF4PB.htm)
Dry 304C (580F), wet 210C (410F).
:cheers:

SFBayV
11-01-08, 03:02 PM
You deff have a leaky slave the guy at the dealer is either a tard or is just trying to get you out of there.

When the clutch disc and pressure plate wear in the V (just like all single disc setups in any car Vett, Honda, whatever) they only lose a few thousandths thickness and this will not contribute to the clutch slave fluid level lowering on any car.

Sorry my bench racing friends but there is not enough meat on a single disc clutch setup to do that.

Take you car to the dealer and break out the manual in front of the idiot that was helping you last time. It basically says the fluid is good for the life of the car and if it is low or empty take the car to the dealer immediately.

My car is suffering the same fate our hydro throw our bearing is a POS and is leaking the bad part is that it is leaking on the clutch itself and will deff shorten the life of your clutch if not ruining it all together. I've felt my clutch developing hot spots lately and I feel a total replacement under warranty coming soon.

If you guys look there have been people who have replaced our POS throwouts with a Corvette one with some mods (of course)


The clutch fluid doesn't drop as the disc "wears".
Unless you are abusing it the clutch really doesn't wear in a measurable sense and if it does you don't know how to drive a stick.

The fluid does go down, it turns black, it will even gel up if you ignore it.
I have seen this a lot and I think that temperature combined with component composition just wears the fluid out.
I have yet to see one of these systems leaking anywhere, at first I was confused by the apparent fluid loss, then I realized that something about the system just breaks the fluid down and makes it do this... don't ask me for a scientific definition, I can't give you one. All I can say is check your fluid, when it turns black change it out and flush the clutch hydraulic circuit and you won't believe the difference. This appears to be a badly overlooked maintenance item and we may see more of them than any other dealer I have heard of.
The manual calls for a DOT 3 fluid, GM actually makes a dedicated DOT 3 clutch fluid, but brake fluid will do.
A lot of guys have opted for DOT 4 but we haven't seen whether or not it is prone to the same issues.


I subscribe to the 2005 V technical bulletins and there is no such bulletin in my set.

Guys, again, thank you for all of the information. I greatly appreciate all of your assistance and support.

On my last visit to the dealer, I'd asked the service adviser for a copy of that bulletin and he gave me one. What's below is a quote from a section of this document. See the section which I've underlined and see if makes sense.

Document ID: 1520345

From the section: "Clutch Operating Members"

"The clutch release bearing is moved by the actuator assembly to move the release levers which move the pressure plate to the rear, thus separating the clutch disc from the flywheel when the clutch pedal is depressed by the driver. A piston return spring in the actuator cylinder preloads the clutch linkage and assures a small load on the release bearing with the actuator assembly at all times. As the clutch disc wears, the diaphragm spring fingers move forward forcing the release bearing, actuator assembly and pushrod to move. This movement forces the actuator cylinder piston to move forward in its bore, consuming hydraulic fluid from the master cylinder reservoir, thereby providing the SELF-ADJUSTING feature of the hydraulic clutch linkage system."

Cory

ewill3rd
11-01-08, 03:43 PM
That is not a bulletin, that is in the description and operation section of the manual for the clutch and it covers the base car transmission and V transmission systems. It is generic information.
The clutch disc is about 1/4" to 1/2" thick, it can't really "wear" very much. This "adjustment" would hardly be noticeable to the naked eye (even if you had it apart) and would barely displace any fluid.
Yes that information is true, but it isn't justification for the lower fluid level.
What it all boils down to is be sure to keep an eye on it and service it when it looks gnarly.
;)
They took care of you right?

SFBayV
11-01-08, 04:17 PM
That is not a bulletin, that is in the description and operation section of the manual for the clutch and it covers the base car transmission and V transmission systems. It is generic information.
The clutch disc is about 1/4" to 1/2" thick, it can't really "wear" very much. This "adjustment" would hardly be noticeable to the naked eye (even if you had it apart) and would barely displace any fluid.
Yes that information is true, but it isn't justification for the lower fluid level.
What it all boils down to is be sure to keep an eye on it and service it when it looks gnarly.
;)
They took care of you right?

Not as of yet. I picked the car up on Wednesday evening and the clutch still chatters. They bled the system along with some other issues resolved by replacing the shifter and differential. The occasional chattering of the clutch and the low reservoir level were my primary concerns. At this point, they're telling me that the intermittent clutch chatter is normal and is attributed to normal wear. They've also said that if the problem gets worse then they'll have a more in depth look. I'll taking it back to them next week for other work, and I'll reiterate my contention that wear has nothing to do with fact that the reservoir was empty.

Cory

ewill3rd
11-02-08, 03:54 PM
I don't know if it is worth arguing the cause of the low fluid. Sounds like that is fixed.
I'd concentrate on the driveability issue.

SFBayV
11-02-08, 11:45 PM
I don't know if it is worth arguing the cause of the low fluid. Sounds like that is fixed.
I'd concentrate on the driveability issue.

What they did was bleed the clutch system. They haven't acknowledged any type of a leak. My concern is if there is a leak, could the fluid have gotten on the disc and pressure plate which in turn may have caused the clutch chatter.

I'll have it back at the dealer either later this week or next week. They apparently bent the driver side rocker molding when they had it on the lift. They had to order another molding and they'll need to paint it prior to replacement.

ewill3rd
11-03-08, 06:53 AM
They are not lifting the car properly, hopefully they learned there lesson.
I posted a picture of proper lifting points on the V somewhere.
Glad to hear they are going to fix it for you, I have seen some really bent up ones.
That was a lesson I learned about lifting cars around 12 years ago, never lift them on a lift using the front pinch weld flange.

I seriously doubt there is a leak. From a technical standpoint it would take some work, or a specific kind of leak to get fluid on the clutch. If the slave were to leak it would run down inside the bell housing and come out at a place that would make it look that way, but really it shouldn't without some sort of external force acting on it.

SFBayV
11-03-08, 12:36 PM
I think it would depend where on the slave the leak is if it were indeed leaking. If the leak is at the furthermost forward area of the slave, it would have a much greater chance of contaminating the clutch. The fact of the matter is, that the reservoir was empty as was a portion of the line. That fluid didn't evaporate. If it did leak at the slave, it would make sense. The clutch chatters, but it still bites tightly. I can accelerate uphill in 6th gear without any slippage, so I don't feel that wear is the issue as the dealer would lead me to believe.

There is also a small rectangular opening at the bottom of the bell housing which would allow any fluids to drain down and out. I'm going to have the dealer take a look into that opening to see if they can find evidence of contamination of brake fluid or engine oil.

I had a 1970 Camaro which had a leak at the main drive bearing retainer of its Muncie transmission. The clutch was contaminated with gear oil and chattered as a result.

Cory