Hi guys well I just shipped my 2006 ls2 off to get some mods and tune done to it. I was speaking to the shop owner today who seems to think I may need a new clutch. He told me the clutch was acting funny and not engaging until the very end. Prior to shipping the car to him I had no problems. No slipping or grinding or any problems going into gear. However I must say though that after your foot leaves the floor with the pedal it does take a long time before the clutch actually engages. But I've read on here that's a normal thing for some of the c6's. Anyways I'm looking for some advice on what the problem could be or if it's just the clutch pedal that he's not used too.I don't think the clutch is gone.

 

are you the original owner? how many miles on the car?

 

The C6 does have a notoriously high clutch pedal. Mine would not grab until the very end and had very little travel even at only 21,000 miles. If it's not slipping then it's probably fine. Try to start out in 3 rd gear and see if it slips any.

 

Check the clutch fluid. If the fluid is back in the tank, its needs to be changed.

The clutch fluid line has three orifice restrictors in it to slow down the clutch engagement to save the drive line, and when the fluid is contaminated with clutch dust, it slows the return of the fluid back to the master cylinder even more.

As for changing the fluid, the hard way is to power flush it since getting to the slave cylinder bleed valve is on top of the back of bell housing, but gets it done one shot. The easy and slow way, the ranger method of fluid change that may take a few times instead.
Note: Ranger method is more of a upkeep method, so once you get the fluid clear, your doing tank changes every few fill ups to try to keep it clear.

As for release and engagement points on the pedal with the stock clutch, it more on the top of the stroke, then deeper in to the stroke instead. As stated, third gear start will tell if you if the clutch is slipping (once all the fluid has been driven back to the master cylinder to all the pressure pad to fully lock up).

 

yes , this info is important to know. hands down the number one reason for clutch failure outside of abuse is multiple drivers.

 

And also, what kind of driving has been done mostly. Freeway driving is much easier on a clutch than crowded city driving.

 

My car has only 30k miles and I had to replace it. Our clutch are known to be weak if abused a little. Check it out.

 

OK so when your clutch went what signs did you have to make you think the clutch was going, mine is showing no issues at all. Thanks.

 

Thanks for the great advice I'll let my shop know. My car has roughly 60,000 miles on it. Not sure if its the original or not, what is the general mileage on these clutches before they need to get changed roughly???

 

What Dano said, check and change the fluid in your clutch master cylinder with Dot 4 brake fluid. If it was me and the clutch was not slipping, for peace of mind I would add a ticks master cylinder, that will push a ton more fluid to your clutch to help with proper clutch function.

FWIW I have beaten and abused my stock clutch for 20k miles and it just started to feel less than positive at high rpm shifts, this is at 640 rwhp. When I changed the clutch the pressure plate had some hot spots on it and It had plenty of material left on the clutch itself, I changed it right at 48k miles. The clutch did pretty damn good considering the life it led.

I would avoid a clutch change at all costs if you could. 10 hours labor + the clutch and flywheel.

 

There are many C6s that have over 100,000 miles that have never had clutch replacement. The life really depends on the driver, the driving and the treatment.

 

Forget mileage for a second, and think what I wrote above about the restrictions in the lines, hence slows the engagement of the clutch when you let the pedal out to save the drive line from abuse.

When guys try to burn burn out by dumping the stock clutch, what happens is the clutch ends up slipping and in fact, spins and burns the clutch out instead of the tires spinning instead. As the fluid get worse and worse contaminated, it just makes the engagement even slower as you are letting off the pedal (for the fluid to flow back to the master cylinder out of the slave cylinder), and what you considered normal driving, could end up being a lot of initial clutch spinning instead (same are riding the pedal).


So on that note, normal use of the clutch without abusing it (read make sure that the clutch is fully locked up before you hard throttle on) and having a clutch last 100K miles is not unheard of.

On the other hand, hard take offs where the clutch is just slipping instead of fully locking up to begin with, or fluid so contaminated that it takes the clutch much longer to achieve full lock up/slipping on a delayed initial lock up as you use it each time), and you can cook the clutch in a mater of 10K miles are less by abusive driving.



So lets back it up and work from the inside out on the problem,

3 gear start, get the car rolling, then once you know the clutch is engaged (give it a half second with your foot off the clutch pedal), pin the gas to the floor and watch the RPM verses the MPH gauge. If the two stay linear together, then the clutch disc is holding fine. If the RPM's take off/climb in a non linear fashion with the MPH gauge, the clutch is slipping and the problem at hand.

Next the throw out bearing, and its part of the above test, as well listening for how it sounds. There should be no bearing noise, and if you are getting bearing noise, then either the throw out, or pilot bearing is shot.

Now back to the fluid, and with it clean, watch the fluid level in the fill tank. If is start dropping, then you know that you have a leak in either the master or slave cylinder.

Now the fun one that is a PITA to trouble shoot, Although the cylinders are not leaking, it could still be the plungers/walls in either worn out that is not allowing for a pressure build up between the two.

In the slave cylinder, since the plunger is the same as the body seal, problems where will end up with the fluid dumping out past the seal/plunger and you will see fluid lose in the tank.

In the case of the master cylinder, since it has a plastic housing/walls, the walls of the cylinder and plunger may be scored too bad to allow a pressure build up in it, but since its a semi closed system, it could be bad without leaking.


To sum it up without test driving the car, hard to pin point the trouble. But on the same token, if you have a shop that is too fast to just jump at the problem as a clutch problem without verify that the master cylinder is not the problem instead, have another shop take a look at it.

Lastly, if it is the master cylinder that is the problem child and you are paying for this repair on your own dime, forgo using another stock master cylinder, and have it replaced with a Tick/Tilton master cylinder instead. The Tilton master cylinder is steel walls so you don't run into wall scoring problems as fast, as well as the two piece line that comes with it does away with two of the three line orifice restrictions. The fast that it will push more fluid per stoke is an added bonus, since with the cylinder adjusted correctly, the engagement point of the clutch to pedal is lower in the stroke, instead of right at the top with the stock cylinder.

As for if the drive line does need to be pulled to work on the clutch, min have a remote bleeder line installed on the new slave clinder so power flushing of the line becomes a snap to power flush the line , and even think about going to a Tilton master cylinder with the solid one piece fluid line that has not orifice restrictions in it. The trade off her is that you can get stupid and clutch dump since it will destroy the drive line clutch no longer burning out to protect the drive line), but on the other side of the coin, does make letting out the clutch pedal more clutch feel responsive instead.


P.S. If the drive line needs to be pulled to work on any part of the clutch, change all the clutch parts out while they are in there (pilot bearing/flywheel, disc and pressure plate, slave cylinder, and even have then check the bearings/coupler/rear axle seals in the drive line while they have it out). As stated, dropping the drive line is a $1K easy in labor, and even if you have to drop a grand in parts to get it all back up to new condition, it going to save you a grand if it is to be pulled later.