I have 740nm clutch fitted. Life thus far = 30k. Clutch not abused - not slipping. After a short weekly trip - 3000 miles (non stop driving 600 miles per day) my clutch developed a slight judder when slowly pulling from a standing stop between 1000-1500rpm. If I increase the revs, judder doesnt occure but it definitely wasnt there before. Otherwise all fine. Any ideas? Anyone has this?

 

Most likely the clutch hardware (needle bearing, throw-out bearing, guide fork, disc and pressure plate) but could also be the clutch accumulator (membrane failure). My bet is that it is a bearing or the disc.

 

Clutch accumulator done not long ago so that's most likely not it. So if the hardware is the case, is it drivable or in need of an immediate fix? What does bearing or disk job entails?

 

What brand of clutch, is it a multi disc clutch?

 

Is it temperature dependent, that is, only when it's damp and cold and goes away when warmed up? If so, then probably nothing to worry about.

 

Huh. Don't know. Tuner installed it when car was flashed. I think it's sach uprated to 740nm. Straight OEM replacement type.

 

I think it's the other way round. It happens when the car is warm. But yes I feel that it comes and goes. Especially if I increase the revs slightly when pulling off it is definitely not there.

 

The more I test the more I feel perhaps it is not the clutch. My engine has a slight vibration ( empty seat next to me shakes a bit ) it feels like this vibration translates a bit to drivetrain. Could it be the engine mounts? What are engine mounts failure symptoms?

 

Wakey wakey...

I'm having this same set of symptoms. Smooth when cool, shaky when warmed up. Any resolution to this?

-V

 

Not much you can do without dropping the tranny.

Try an E-Gas calibration. With the key off and your foot off the gas pedal the whole time turn the key to the #1 position and leave there for 60 seconds. Turn off for at least 10 seconds. The next time the engine is started the calibration will be complete.

Beyond the above, about all I can advise is to be sure if there is a clutch fluid flush/bleed service that this is done.

Be sure the engine is in good tune.

You can have the engine and transmission mounts checked for any signs of degradation.

Often a clutch judders because of overheating. This overheating causes the flywheel and pressure plate surfaces to develop hard spots and these have a different co-efficient of friction and as the clutch disc makes contact and begins to grip these hard spots let the disc slip a bit and that's the judder.

A worn disc can judder too if it wears enough the rivets start to make contact with the flywheel or pressure plate.

There is the rest of the clutch related hardware, the linkage and very important the clutch control shaft and its needle bearings. Everytime my Turbo's transmission has been out the tech has always replaced these bearings and their caps/seals with new ones.

If you can't live the judder and none of the above things help then you are faced with I guess dropping the transmission and giving the clutch hardware a good inspection and replacing the disc, pressure plate, release bearing, needle bearings, and either resurfacing the flywheel if is it otherwise ok or replacing it.

 

I just went through this last week. It's very possibly the accumulator, even though you said yours is reasonably fresh.

The symptoms I was experiencing was the clutch judder, especially in first and more so in reverse gear. I would also feel a faint pulsation through the clutch pedal, even barely pushing it down. It seemed worse at temp. I've experienced this before with my stock PP and clutch disk.

I now have the stock slave/accumulator setup, and high clamp force 764 PP.

With this setup, the judder is even more prominent with first being hard to engage at times, and having to put the clutch pedal all the way to the floor.

I suspected the disc out of round, needle bearing, PP, etc. Fortunately it wasn't any of those as I'll take a bad accumulator over those anytime.

I was able to isolate that it was the accumulator by doing the following. Try before starting up the car, to empty the pressure in the accumulator (if you even have any assist left). Press the clutch 10++ time until you feel the boost taper off dramatically. Then start and drive the car. Mine would feel great again for about a 10 minute drive, then exhibit the judder behavior again.

Theory goes that with a worn accumulator, the internal diaphragm is too worn to absorb the pulsations of the hydraulic pump/assist. The pulsations manifest within the clutch throw itself, causing rapid on/off engagement , hence judder. At least this was my case.

My drive this morning was smooth as butter again. I would address it quickly, as it's been known a worn accumulator will take out the slave. Possibly because if the pulsations manifesting on the slave actuation itself, wearing the seals.

 

Interesting.

My 2003 Turbo had a bad clutch accumulator but no clutch judder though. Stock clutch. I could feel some mild pulsing through the pedal when working the clutch which is normal with a bad accumulator but again no clutch judder.

I like the idea of the pulsations causing the clutch slave cylinder to wear out. It was just a week or two after the clutch accumulator was diagnosed as being bad that the slave starting leaking.

To be sure, it would be nice if the OP's clutch judder problem is due to a bad accumulator. To address that is a lot less expensive than dropping the transmission and possibly refreshing some/all of the clutch hardware.

 

a plate could well be glazed.

from a "clutch page" lol

"Chatter: Clutch chatter is an excessive vibration felt just as the pedal is being released and the clutch is beginning to engage. To test for this condition, set the emergency brake, depress the clutch pedal, and rev the engine to about 2000 rpm. Slowly release the pedal so you can feel when the clutch starts to engage. This is the point a clutch will begin to shudder. Clutch chatter is typically caused by glazed or oil contaminated clutch facings. The engine and transmission mounts and alignment dowels should be checked for misalignment. This will cause a major shudder and clutch chatter, damaging the discs torsion springs and clutch facings."