Violent Clutch-related Judder

[Anthony 1,003]

Bit of help here if anyone's got any suggestions, as this fault is really baffling me now.

 

I'm borrowing Kate's 205 Mi at the moment and sorting out a few problems on it for her, but struggling with the clutch-related judder that it has developed that doesn't really make any sense.

 

If you put the car in 1st gear, and pull away as normal, it will start to move forward smoothly and then after a moment you get a *very* violent juddering that shakes the entire car, like extreme axle tramp (that's the best comparison that I can come up with). It doesn't seem to make any difference whether it's the first pull away in the morning (ie stone cold clutch) or if you've been slipping the clutch a bit to get it hot, and nor does it seem to make much difference if you pull away slowly with next to no throttle, or pull away briskly with a fair whack of throtttle.

 

As soon as you're rolling forward fast enough that the gearbox input shaft and flywheel speed match (ie the clutch is no longer slipping), the juddering stops completely. When rolling along at idle speed in first gear, you can press the throttle and it'll go with no juddering whatsoever.

 

Logically based on the above, you'd imagine that it was a clutch related fault, right? However, this is where the oddness starts. You can pull away fine in 2nd gear with no judder whatsoever (it runs an Mi box, so 2nd is short enough to pull away with minimum extra clutch slipping), and it doesn't judder in reverse either from what I can tell. You can also apply the handbrake and sit there on the biting point in first with no juddering at all, even giving it alot of throttle so it's pulling the nose up hard and straining on the leash. However, start to release the handbrake so that the car moves forward, and the juddering appears.

 

It's difficult to say precisely as the juddering is so violent at times that you have to dip the clutch just for mechanical sympathy (and to keep my fillings in!) but I'd say that when it's juddering the car is rolling at a constant speed, and not jerking back and forth as you'd expect if the clutch was grabbing and releasing.

 

The flywheel on the car was skimmed true when I rebuilt the engine around a year ago, and I believe that the clutch fitted was new or atleast nearly-new. The car is running full Group N engine mounts that subjectively look alright, and the gearbox is still firmly attached to the engine. Nothing has changed that I'm aware of since the car working and this fault appearing, and other than this, the car is driving pretty well now.

 

Has anyone got any ideas, as like I said, this is really baffling me. Initially I thought it was a clutch issue, but seeing as it only happens in first and whilst moving it doesn't really fit with a clutch problem. I think that I'm going to remove the bonnet and see if it looks like its the engine violently rocking around that's causing the juddering (as it feels like there is a small amount of driveline-shunt when you come on-off the power), as I don't want to needlessly drop the gearbox and I'm at a loss for what else to try in all honesty

[Rob_the_Sparky 9]

A muse that may or may not help (thinking aloud so to speak):

 

What you describe almost has to be a friction thing, e.g. something rapidly catching and releasing, or a backlash thing (e.g. there is slack in a joint when force is reversed).

 

However, for it to be backlash then something must be reversing the force in the first place, and that brings us back to friction...

 

My immediate reaction to the first half was small amounts of oil on the clutch.

 

A possibly daft suggestion. Axle tramp, could you have a totally shot shocker and the front wheel is bouncing up and down????? Seems very unlikely but bar the clutch I'd suspect tyres as they are the next friction based "joint". First gear will put more torque on the components than 2nd will.

 

Could it be something going wrong in an exotic diff? Don't know anything about their failure modes though.

[boombang 2]

What is it like in 3rd gear?

[Anthony 1,003]

My immediate reaction to the first half was small amounts of oil on the clutch.

That was my first guess before I drove the car and discovered the oddities. I tried getting the clutch very hot to "burn off" any contaiminants (read - hill start in fourth ) but it didn't seem to make any difference to the juddering afterwards, only leaving a nasty smell in the cabin for the rest of the day

 

The car did burst a coolant pipe a while ago and covered the top of the gearbox in coolant, and I guess some of this (together with washed down oil) would have found its way into the bellhousing and clutch. However, the problem didn't appear until some time after this, so I'm assuming the two aren't connected.

 

A possibly daft suggestion. Axle tramp, could you have a totally shot shocker and the front wheel is bouncing up and down????? Seems very unlikely but bar the clutch I'd suspect tyres as they are the next friction based "joint". First gear will put more torque on the components than 2nd will.

Shocks (Bilstein Group N coilovers) and rest of the front suspension seem to be fine, and the passenger driveshaft/hub and drivers wishbone have been replaced (for an unrelated reasons) with no effect.

 

I thought about the torque thing, but the torque at the wheels in first pulling away gently would still be less than pulling away rapidly in 2nd I'd have thought. Also, reverse I believe is shorter than first and hence more torque still.

 

Could it be something going wrong in an exotic diff? Don't know anything about their failure modes though.

It's running a Quiafe ATB and not sure if they can fail in this manner, but the diff does seem to work fine.

 

What is it like in 3rd gear?

The one time I tried it pulled away fine in both third and fourth, although clearly the clutch is getting more abuse than I'm comfortable giving to do that. Haven't tried 5th (I'm not that mechanically unsympathetic!) but see no reason that wouldn't also be fine.

[Richie-Van-GTi 71 2 Cars]

Have you tried dumping the gearbox oil and checking for fragments of first gear in there? Based on coolant dumping on box etc, possibly its got inside the box and contaminated the oil giving issues with viscosity etc. I know it doesnt take much water to knack a pug box given they only take 2 litres of oil to start with. Also a lot easir to dump oil than remove box.

[luggy 13]

Hi Anthony

Take it to a private road take the bonnet off and get a brave assistant to kneel/hold on for dear life while you drive, see if they can see or hear anything strange. Sounds drive related either from the box or the diff. What about putting the front on axle stands. See if the wheels spin freely in neutral and run it from 1st to 5th to see if the problem is load dependant, dont know the reasoning just thought I'd suggest it. Id go with Richie and drop the gearbox oil and see what it says, if you get nothing from that put a standard diff in see if you get the same result.

[sorr 0]

I had the same issue and it drove me nuts given it did not make sense, as in first grear judder so bad I thought the car would come appart, but no judder in higher gears. Also i could not recreate the issue with the car on axel stands.

 

A possible correlating feature seems to be be a coolant leak as mine too dumped it all over the gearbox. After many hours of fault finding and checking for anything loose (unlikely due to my obsession for thread sealant ) I could find nothing.

 

My rather unscientific solution was to utterly abuse the clutch. I dove it along while slipping the clutch and after doing many cycles of this it was fine. At the time my clutch was a 1000 mile old Valeo so I do not believe it could have been realease arm or bearing issue.

 

So in short I would be abuse the clutch and see what happens.

[PumaRacing 2]

However weird the symptoms might seem I wouldn't try to overthink it. Mechanical systems do weird things and often not totally logical ones. If it was the gearbox it would do it when the clutch was fully engaged and even though it seems strange that the judder happens in first gear but not second or reverse I still think you'll find it's a clutch issue.

 

You might also want to put a dial gauge on the flywheel to make sure that the skim it had didn't actually make it eccentric rather than true. Easily done if it wasn't held in the lathe properly. Also these flywheels get very hard carbide spots where they overheat and a lathe tool often won't cut those flush. They need grinding rather than turning. Weak or broken clutch fingers or missing damping springs in the friction plate could be the problem too as could a sticking release bearing.

[Edd-XS 0]

I know it sounds extreme, but would replacing the gearbox with a similar one be a good idea? If it were me Id be so fed up with the bloody thing by now i'd just find another decent box and shell out for a clutch! whichever bits still decent and not up s**t creek, flog it on and get some money back...?

Edd

[Guest miamiali]

My new miami does exactly this. I was told it may be the engine mount though!

[welshpug 1,657]

my ZX does exactly this, and I know the clutch is FOOBAR'D if you change down the gears at lower than 4k without matching the revs vaugely the dash looks like its gonna fall off! give it stick in any gear once its engaged though and it holds, but try and slide it in at idle and you get judder.

[Pugnut 9 1 Cars]

my high performance astramax 1.7d did this before the clutch packed in completely. when removed, the damping springs were gone(no longer present) and the friction plate was in two parts. the friction plate was turning but the splines-input shaft wasnt.

 

It'll get worse, eventually i had to take off in 4th. it would leap forward for a few yards and stop (in gear clutch still engaged) then catch again until you eventually get some momentum going.

 

it all started with the nonsensical judder.

[C_W 3 1 Cars]

When I fitted the wrong clutch plate to my Mi16 it worked fine for a while but as it wore very slightly the springs on the plate gradually wore against the flywheel bolts (it made a light squeaking noise setting off that I could never work out where it was coming from), then one of the springs snapped and it was as described above.

 

The clutch plate was for a 2.0Mi16 and it seemed almost identical to the proper one except the friction plate wasn't offset enough from by a few mm meaning as it wore the centre go too close to the flywheel bolts. It worked perfect;y well up until the spring snapped.

[Anthony 1,003]

Cheers for the input people - sounds like it is a clutch-related issue then after all, abeilt one with a few different possible causes.

 

I'll try Stuart's suggestion of abusing the clutch first to burn off any contaiminants, as if I'm going to have to drop the box and swap the clutch I don't really have much to lose. If that doesn't help, then I guess it's time to drop the gearbox off and see what's what.

 

Interesting comment about 1.9 and 2.0 friction plates being slightly different and causing this issue after a few thousand miles. I didn't supply the clutch as said, so it's possible that she was given the incorrect one unknowingly.

 

The gearbox oil has been drained since this issue appeared when I swapped the driveshaft over, and the oil that drained was clean and fresh (was only a few thousand miles old anyway, and was the correct 75W80 grade). It was replaced with fresh oil as a matter of course.

[P_205GTi 0]

If not any of the above, try checking all the gearbox bolts are tight sounds silly but you know how easy they vibrate loose and this caused the same symptoms to my car.

[Anthony 1,003]

If not any of the above, try checking all the gearbox bolts are tight sounds silly but you know how easy they vibrate loose and this caused the same symptoms to my car.

One of the first things I'd checked, especially as this car has a habit of spitting out bolts randomly...

[ALEX 98 1 Cars]

I had this with mine a few years back.

I even had the car on axle stands like you did and it ran fine.

It only juddered under load, it ran fine in reverse though:blink:

Turned out that the connection for the ingnition amplifier had come loose.

Edited February 19, 2007 by ALEX

[P_205GTi 0]

damn oh well worth a try, hope you find what is causing it and get it sorted

[Anthony 1,003]

Thought I'd revive this topic.

 

After the engine blew up last month and was removed from the car, we took the opportunity to inspect the clutch and find out what the issue was that was causing all the juddering described above.

 

Well, despite the clutch being new less than a year ago, it was completely f**ked to put it bluntly. The friction plate was down to less than 20% material and didn't look to be worn evenly, and the clutch cover had half a dozen bent fingers on it

 

Flywheel looked to be in excellent condition though.

[Richie-Van-GTi 71 2 Cars]

Could this judder have been an underlying cause for the engine failure?

[kate205gti 4]

just found this searching for flywheel bolt part numbers

 

the cause was actually my gearbox hanging off the bolts had worked themselves loose and the gearbox was at an angle so squashing the clutch cover, etc..

 

if u get these symptoms would recommend checking all 4 gearbox bolts are tight!

[Anthony 1,003]

The bolts were tight when I had the car as that was the first thing I checked - the juddering/vibration had clearly shaken them all loose again between me giving the car back and the engine coming out...