Clutch question cont......

[944_85]

Two weeks ago I poped the question about the shudder, when I take off when the car is hot.
( Not sure how to copy the link to the previous post here.)
After a confirmation drive, it was confirmed that this only happpens when the car is hot, typically in traffic or after a few minute idle on the driveway. However when the car is cold, it is silky smooth.

Today I had the chance to get under the car, to change the gearbox oil, and measured the clutch. I measured through the hole, as descibed in the Haynes manual. According to Haynes measurments are 18mm = new, 34mm = time for a new clutch. However I measured 24mm. So I suppose I have to assume that the clutch material is not at it's end, and that it is only rubber centre which is starting to "disappear". Does this sound sensible? Or could it be something else?

Second question: As mentioned, I changed the gearbox oil, as I have alsmost no history of the car. (Only one fluid not changed yet since the purchase, and that is the brakefluid) While I was draining the old and cleaning the draining hole, I found some small pieces of metal inside. This was a bit of a shocking discovery.
Should I be concerned? Or can this be normal for a 24 year old car, where the gearbox oil might never have been changed?

 

[barrysmith]

The rubber center just falls to bits and the clutch moves from of center when warm but the clutch still works as a clutch, need changing to remove the train judder.

Not uncommon for a small amount of metal fragments, flush the box out and then replace the oil.

 

[zcacogp]

The clutch judder is one of the world's mysteries, as far as I can tell. No-one has come up with a satisfactory explanation for it, although the moving-off-centre one from Barry Smith is a new one to me. I have also heard (or read) theories about local hard spots developing on the flywheel, which need to be machined out, but I didn't believe it as there was no evidence to back that up, and it didn't apply in all cases, which the theorist couldn't explain either.

Suffice it to say that the judder seems to be associated with the rubber clutch only (not the sprung one), and seems to happen towards the end of the clutch's life, but not always. It can be seen as a sign of impending failure, but then some people can get 000's of miles out of a juddering clutch (Paul Smith on here has done six figures of mileage on one.) I changed my old clutch a couple of months ago, partially because it was juddering (and had been for the last 40k miles), and there was wear a-plenty left on it and the rubber centre was totally intact. All I can say is that the new one (sprung, not rubber) doesn't judder and is nicer to use.

Gearbox oil - how big are these fragments of metal? Tiny filings in the oil or lumps the size of sugarcubes (/ coke cans / housebricks / elephants / Canada?)


Oli.

 

[barrysmith]

Its got to move of center, its a rubber middle , now in bits or very soft, and running out of line (not balanced Its a bit like a buckled wheel), its the only part that holds the clutch plate central to the fly wheel,

so when its at its limit ( disengaging) its turning in on it self , thats why the drive train judders its simply trying to break, when engaged with no pressure its back in the center and working ,only time its at fault is when its pressed to disengage and judders like made on engagement for a few seconds.

 

[944_85]

Well the size of small metal bits can be the size of Canada, it just depends to what you comare it to

They were around 1mm by 1mm. Very small I suppose when it comes to a gearbox.

Do I have to have any concerns?

 

[barrysmith]

Are we talking a few or a cup full, you have to remember is full of teeth / gears all interlooking you are bound to have a small amount in a car thats done 75000 plus and 20 plus years old.

Also a clutch thats not working as it should.

If it sounds ok I would'nt be that worried but I would fluss it out and replace the oil.