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clutch damage



Could loose engine/gearbox mounts cause the damage to the clutch cover plate as shown in the photos?

182 clutch1.jpg


182 clutch 2.jpg
 
Many thanks for the reply Rob.

I must admit I couldn't make the connection between the two, but on track I suddenly couldn't change gear when braking heavily and on investigation found some loose bolts on the pure motorsport engine and gearbox mounts. But having tightened everything up and checked the alignment of the engine, gear selector etc the problem persisted. Although it changes gear fine at low speeds ??

Took the clutch out and found the above. All the bolts seemed equally tight, including the 2 on the broken bits, so what might cause the clutch fork to overtravel ?
Is that an adjustment on the pedal?
Just concerned about putting a new clutch in and it happeneing again.

Cheers, Andy
 

Touring_Rob

ClioSport Club Member
Hi Andy no problem. To add more specifically. I can't see any reason for the clutch cover to be damaged by loose engine/gearbox mounts. Someone else might have a plausible explanation?

I'm still quite new to Clios however on a previous car with an AP clutch I used the wrong clutch pedal quadrant which resulted in me damaging the spring fingers on the clutch plate due to over travel. If the clutch bottoms out then there is the possibility that quite a serious amount of force would be effectively trying to lift the clutch cover away from the flywheel, doing this repeatedly could/would fatigue the clutch cover around mounting bolts. Note that each side has broken in nearly the same way - this is probably due to the shape of the cutouts creating a high stress area in each corner of the cutout.

This could also have been due to a manufacturing defect on the clutch cover - as soon as one side of a lug broke the other would fatigue much more quickly and as soon as one side had failed the other could soon follow.

I would get under the dash and have a good look at what ever mech is adjusting the clutch cable - often this is a semi circular quadrant intended to ratchet as the clutch wears so as to keep the biting point in the same place.

Im not saying this is your issue, this is just speculation but likely where I would start looking! For now I would suggest that the loose mounts and clutch failure are unrelated (unless the engine was moving by a lot!).

How worn is/was the friction plate?

Good luck!
 
Thanks for the comprehensive reply Rob,

I reckon you're right in that the clutch damage and mounts are not related. I went down that path thinking the difficulty in changing gear was down to the engine moving in relation to the gear selector, and I got stuck in that mindset.

Before I took the clutch out I did check the fork travel with the engine running and it was 30mm, which should just be in tolerance I think.
The wear compensator mechanism is as you describe, a semi- circular quandrant, but I can't see anything fouling it, and it seems to work consistently with repeated operations.

The friction plate has very little wear as it's only done about 8 outings, race and trackdays, the car's not used on the road, and it only has a puny 176bhp.
It was fitted along with a lightweight flywheel and recon gearbox with gripper plated diff ( from @NorthloopCup , the absolute best mod for going faster around a twisty circuit! ). I got my regular garage to do the work but looking back the only thing I didn't supply was the clutch, and from the bill £115 plus VAT garage price suggests it probably wasn't a genuine Renault article.
To be fair I probably didn't specify, but it might point a bit more towards product failure than another underlying issue

I've ordered an OEM clutch kit from renaultpartsdirect, so i reckon I'll just fit that and keep my fingers crossed. If the same happens again...????
I'll also renew both trackrod ends and lower ball joints while everythings in bits.

On the positive side I've learned quite a bit getting the geabox out. it's taken more than a few hours, and I'm not proud of most of the language I've used while doing the job, but it's good to learn.......just got to put the f@#ki*g b#st@rd back together now!

Cheers, Andy
 

Touring_Rob

ClioSport Club Member
Great stuff Andy - best of luck and let us know how it goes!

My only comment is that you checked the fork travel at 30mm however some of that may well have been with the cover moving? So your 30mm might have been more like 25 (just for figures sake) with a non broken clutch cover.

Also wondering if the light weight flywheel may have been partly to blame here - I could imagine that if it was a different total thickness from stock?

Edit - that probably doesn't matter too much, it likely an issue if the clutch face and clutch cover mounting faces are at different heights to stock which is very unlikely.
 

Touring_Rob

ClioSport Club Member
Also thinking on this more I am beginning to doubt my explanation.

1599075604950.png


As the bearing is moved into the diaphragm spring the pressure plate is lifted away from the flywheel face. If the bearing over travels I guess you could distort the clutch cover slightly leading to longer term fatigue however the force acting on the bearing (do disengage the clutch) is pushing the cover down onto the flywheel and never lifts it hmmm. I would lean more towards (hope for) a manufacturing defect on the clutch cover.

However it would be interesting to measure your friction plate thickness compared with your new Renault one when it arrives.
 
I like that illustration, although I'm reasonably mechanically minded I struggle to retain how all the components of a clutch interact....and if we move on to LSDs then I really get a headache.

Looking at that illustration I would have thought the force of the realease bearing does exert pressure against the cover plate, pushing it away from the flywheel, or at least try to to splay it out from the flywheel.
It's hard to visuaise the forces around the diaphragm spring retainers, which look like pins in the illustration.
The pins pull in on the cover plate, but does that pull the whole cover in towards the flywheel or pull the centre in, effectively pulling the outer edeges away.
TBH the cover seems rigid enough that you are right, the whole cover is pulled towards the flywheel, and in looking for an equal and opposite reaction that of course the the pressure plate lifting away. All clever stuff if I just had the brain cells to understand it!.

I will compare the friction plates, and get back to you with my progress. I really hope this was just a cheapo clutch problem.
 

Crayola

ClioSport Club Member
Were the bolts tight?

The only thing I can think of is that either the bolts were loose and it fatigued that section of metal or someone has been absolutely booting the clutch pedal to the floor and fatigued it that way 😂

Either way it's the first time I've seen that happen! @NorthloopCup you ever seen this?
 
Many thanks for the reply

Yes all bolts were equally tight, or definitely not noticeably loose when I took the clutch out.
These were the top 2, if that is any relevamce.

Generally only me who drives the car, just on track now. Historically I've been pretty light on clutches, the car is 132,000miles and came with all the bills which don't include a new cluch, and we only replaced the original with this one as the geabox was out for the new diff.
But a couple of others have driven the car on trackdays this year, so if abuse could really cause this I'll have a look at the in car videos!

Can you adjust or limit the pedal travel so you can't overforce the release bearing?

Also I can't really visualise why this would make it impossible to change gear at speed, but okay from cold at low loads???

I'd love to pinpoint a cause to try and prevent it happening again, particularly as it's such a job to get at the thing, but looks like I might end up having to put it down to product fault.

Cheers, Andy
 
Given that the damage is at the top 2 holes where the flywheel stopped, I am now concerned that I might have caused this damage in removing the gearbox.
The box was supported on rolling Jack's the whole time, but was a bit difficult to pull away from the locating stud on the front.
If the end of the box had tilted down a bit with the shaft still engaged could it have broken the top of the cover plate?
I didn't notice any sudden movement or noises, and there's no noticeable damage to the spring 'fingers '. Just wondered if anyone has known this happen when removing the gearbox.
Probably just being paranoid but if the clutch isn't the cause of the gear change problems then I could have more serious gearbox issues
 

Touring_Rob

ClioSport Club Member
Many thanks for the reply

Yes all bolts were equally tight, or definitely not noticeably loose when I took the clutch out.
These were the top 2, if that is any relevamce.

Generally only me who drives the car, just on track now. Historically I've been pretty light on clutches, the car is 132,000miles and came with all the bills which don't include a new cluch, and we only replaced the original with this one as the geabox was out for the new diff.
But a couple of others have driven the car on trackdays this year, so if abuse could really cause this I'll have a look at the in car videos!

Can you adjust or limit the pedal travel so you can't overforce the release bearing?

Also I can't really visualise why this would make it impossible to change gear at speed, but okay from cold at low loads???

I'd love to pinpoint a cause to try and prevent it happening again, particularly as it's such a job to get at the thing, but looks like I might end up having to put it down to product fault.

Cheers, Andy

I think its likely that if the cover is moving (due to the broken lugs) that the clutch would not fully disengage making it difficult to select a new gear due to the higher differential speeds between engine and box at higher speeds?

I find this on the motorbike and was nearly ejected at a set of lights a while back. Getting ready to do a launch so had revs at 6k(ish) about to release clutch, moved my hand by a mm and got full engagement where I was planning to slip it in. Reading about it the clutch pates all chatter around at higher rpm and sometimes get caught up in the basket. Wonder if something similar happens here, so at higher RPM the clucth plate is doing its own funky dance meaning you need a bigger gap between pressure plate and clutch plate - if the cover is wanking about you might not be able to achieve the required lift off meaning the clutch drags more?

I think this should be an issue for future Andy, present day Andy will probably just fix it all with the new Valeo :)
 
Thats a LUK clutch, be intrested to know if the pedel feels any different to the genuine one (VALEO) once you have it fitted.

The genuine Valeo should arrive tomorrow, so with any luck I should be able to give it a test sometime at the weekend.
The LUK clutch is way cheaper, so I'm hoping that has something to do with the failure.
When it was first fitted the feel of the biting point almost disappeared, but I'm putting that down to the lightweight flywheel that was fitted at the same time.
It will be interesting to see if some of that feel comes back though.

@Touring_Rob the fact that the clutch plates don't necessarily keep a flat rotation could well explain the problem, particularly if you add in everything heating up.
Could explain why gearchange is fine cold and low revs, then suddenly blocks after some use. Leave idling in neutral for a time to cool down and everything works again. Let's hope so anyway. Many thanks for your help, and glad you didn't get thrown off the bike!
 

Touring_Rob

ClioSport Club Member
The genuine Valeo should arrive tomorrow, so with any luck I should be able to give it a test sometime at the weekend.
The LUK clutch is way cheaper, so I'm hoping that has something to do with the failure.
When it was first fitted the feel of the biting point almost disappeared, but I'm putting that down to the lightweight flywheel that was fitted at the same time.
It will be interesting to see if some of that feel comes back though.

@Touring_Rob the fact that the clutch plates don't necessarily keep a flat rotation could well explain the problem, particularly if you add in everything heating up.
Could explain why gearchange is fine cold and low revs, then suddenly blocks after some use. Leave idling in neutral for a time to cool down and everything works again. Let's hope so anyway. Many thanks for your help, and glad you didn't get thrown off the bike!

Thanks Andy, yes glad I didn't come off either! Best of luck and hope all goes to plan for you.

My newly fitted Valeo has a very definite biting point feel although I do have a standard flywheel.

Rob,
 

NorthloopCup

ClioSport Moderator
Were the bolts tight?

The only thing I can think of is that either the bolts were loose and it fatigued that section of metal or someone has been absolutely booting the clutch pedal to the floor and fatigued it that way 😂

Either way it's the first time I've seen that happen! @NorthloopCup you ever seen this?
It’s not one I’ve ever seen mate and I’ve seen valeo clutches doing destructive things. The genuine Renault valeo doesn’t though - go figure.
 

NorthloopCup

ClioSport Moderator
Thanks Andy, yes glad I didn't come off either! Best of luck and hope all goes to plan for you.

My newly fitted Valeo has a very definite biting point feel although I do have a standard flywheel.

Rob,
You need to reset your clutch ratchet. Take the cable off at the box and pull it all the way out. That lifts the clutch pedal in the car and should reset the ratchet.
 

Touring_Rob

ClioSport Club Member
You need to reset your clutch ratchet. Take the cable off at the box and pull it all the way out. That lifts the clutch pedal in the car and should reset the ratchet.

Ahh great thank you. I replaced the clutch cable at the same time and it looks reset. I meant more specifically that the Valeo feels normal ie, it has a biting point feel about in the middle of travel.
 
Many thatnks for the help all.

Everything back together and no nuts or bolts left over, always a good sign.

Tested fine with a short trip up the road, no issues with the gearchange after warming up and hard braking as before.
Can't test it too much on the road, as the car has numberplates, but..............

Anyway I'm confident enough in the fix to book a trackday at Lydden Hill in a couple of weeks' time, when I'll probably break something else.

The valeo kit did seem altogether more solidly made, but maybe that's just my imagination.
Friction pad thickness was the same, so hardly any wear on the broken LUK one.
Perhaps we'll never know why it failed like that, don't really want to find out by it happening again!

The clutch pedal is a touch heavier, which make sense if the cover is no longer flexing.
No difference in the biting point, still hardly noticeable so that must be the lightweight flywheel.

Cheers, Andy
 
Help! Update after Lydden Hill trackday yesterday:

Absolutely fine for 3 sessions, approximately 45 track miles, and only 90 downchanges and upchanges.
Downchanges from 3rd to 2nd braking from 90mph to 45, and 70 to 30
Then just the same as before, after a downchange suddendly unable to select any gear?????

With the engine running you cannot select any gear.
However with the engine off you can select a gear with the clutch depressed and start the car without it hopping, let the clutch up and the car moves.
So there must be a certain amount of disengagment when the clutch is depressed, but not enough to change gear, there is then some level of re-engagement when you lift the clutch, but again not fully as when driving it onto the trailer in first with clutch up there was a full on clutch-slipping-burny-smell up the ramps.

I can't believe the cover plate has broken again, but maybe it has come loose?
I torqued up the 6 bolts as instructed, having tightened gradually in a star pattern etc. Are you supposed to use threadlock?

I have checked the travel of the clutch fork and at 29mm it should be in tolerance.
The fork is still engaged in the plastic part of the release bearing, and is holding the bearing against the spring fingers, as far as I can see with a light through the fork aperture all looks ok.

Anyway I've obviously got to take the floody bucking gearbox out again, so will update in due course, but if anyone has any ideas about what might be going on I'd be grateful to hear them, even if it's accusing me of clutch abuse!

Ta Andy
 
No mention of threadlock in the renault maual just says
Gradually screw in the bolts in a star formation, then tighten the cover mounting bolts to the specified torque. 20 nm

Many thanks for the confirmation.
Unfortunately no time this week to take the gearbox out, but should get onto it at the weekend. I'm a bit intrigued as to what I might find.
 
What release bearing did you use? And did you put it onto the fork properly?

Sounds stupid but I find its always something trivial that messes s**t up

The bearing was the new one that came with the valeo kit.
As for fitting correctly, I think so, but could easily have cocked something up! From memory:
Having fitted the clutch and removed the plastic alignment tool I greased the gearbox shaft sleeve with the grease that came with the kit. The sleeve looked in good condition, no cracks or anything.
Then slid the bearing onto the sleeve, located the end of the fork into the plastic lugs.
I think then I loosely wired the top of the fork to the aperture in the casing, to keep the bearing held back on the sleeve so it didn't try to slide off the shaft as I offered the gearbox up.
Gearbox shaft seemed to locate really nicely through the clutch and everything pushed together more easily than I expected, I was ready for more of a battle and excessive swearing!
Once all that was bolted and torqued up I held the fork, cut off the wire, located the dimple in the fork on the rubber pivot, pulled the c;utch cable to full extend and hooked it back onto the fork.
Measured the travel at the top of the fork with the clutch depressed, much the same as it is now, maybe 30mm rather than 28, but still all within range I think.
After that road test etc, all seemed ok.

Even now the fork, bearing, lugs etc all feel connected as they should be.
I've tried to take a photo through the aperture and I think it still shows the bearing correctly located on the spring fingers, but PLEASE if you spot anything wrong in the photo or what I,ve said above please let me know, I definitely don't want to make the same mistake twice!

20200921_160842_resized.jpg


20200921_160710_resized.jpg


Many thanks
Andy
 
Certainly looks like something there.
I've got one of those magnets on an extendable aerial type thing, so in the morning I see if I can get it in there and pick anything up.

Where could it be coming from, the bearing grinding on the spring fingers or something?
 

NorthloopCup

ClioSport Moderator
Did you fit the clutch plate the correct way round? Sometimes they have a flywheel side/pressure plate side - just an off the top of my head thought mate.

Only other thing can be the release bearing has failed, but get a magnet on it asap! If that swarf is aluminium, it’s the strap on the cover failed and machining your gearbox = very expensive problem to fix.
 
Did you fit the clutch plate the correct way round? Sometimes they have a flywheel side/pressure plate side - just an off the top of my head thought mate.

The old LUK plate had written on it 'gearbox side', the new valeo one didn't have anything written on it, but the two sides were obviously different and pretty much identical to the LUK one, so i fitted it the same way round. The 'gearbox side' sticks out a bit more than the flywheel side, so not sure it would have fitted the other way round. I hope that's right.

I will let you know what I find tomorrow.

Thanks all for the help
 


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