Hydraulic clutch question

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jgra1
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Hydraulic clutch question

Post by jgra1 »

all, wonder if you can dig into an issue I have.. just need theories really 😉

I changed the clutch (as part of a major restoration) on my X244 Boxer / Relay van a few years and only 10,000 miles ago. The replacement clutch was a Borg beck, so not Valeo but good enough..

I have noticed some rattling recently, which disappears as soon as the clutch pedal is depressed. Over the weekend I removed the transmission, not a small task and disappointing so soon after a new clutch.

I can’t find anything wrong! It just looks and feels like a 10K clutch should.. release bearing all smooth, nothing untoward happening there. These clutches work by pulling the bearing away from the flywheel. The plate looks good, the 4 shock-absorbing springs don't rattle. The only thing I have noticed is there is a clearance between the slave pushrod / actuating fork / release bearing - which all gets taken up with any pedal.

Could this clearance be the rattle? If I wiggle the release arm from outside the box it certainly makes a noise..

To my question, should a hydraulic clutch have a preload to avoid this scenario, and as it’s hydraulic, how to you adjust the preload and therefore take up the slack? Any thoughts appreciated! Will have to put it all back together in a couple of days as a bit of wasted effort really, and will still have the rattle…

I can just change the slave, and bleed.. but I would like to know why I should ! 😊
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Re: Hydraulic clutch question

Post by Gibbo2286 »

Does that not have a dual mass flywheel? They rattle before failing.
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GiveMeABreak
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Re: Hydraulic clutch question

Post by GiveMeABreak »

No, solid flywheel on this one Eric (2004)
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Re: Hydraulic clutch question

Post by mickthemaverick »

Just an out of the box thought - if the rattle goes away when you depress the clutch does it come back if you leave the box in neutral and release the clutch again? However I assume it does not come back when you engage a gear and release the clutch so maybe the problem is with an idler bearing in the gearbox? :?: :)
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CitroJim
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Re: Hydraulic clutch question

Post by CitroJim »

mickthemaverick wrote: 15 May 2023, 16:18 Just an out of the box thought - if the rattle goes away when you depress the clutch does it come back if you leave the box in neutral and release the clutch again? However I assume it does not come back when you engage a gear and release the clutch so maybe the problem is with an idler bearing in the gearbox? :?: :)
A good check to do Mick :) I had a high-mileage Xantia HDi (ML5 box) that rattled in neutral that could be mitigated with gentle clutch depressions and that was definitely a gearbox issue. It never got any worse in my ownership or the next so even if it is a bit rattly in neutral it's unlikely to fail any time soon...

It could well be the clearance between the slave cylinder push-rod and the fork John. I know from the hydraulic clutch on the Xantia ML5 'box there is a small amount of preload on the push-rod... and it's quite conceivable the fork could happily rattle away in neutral with the engine idling...

Does it go away if you rev the engine a bit?
Jim

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Re: Hydraulic clutch question

Post by jgra1 »

thanks Mick and Jim.. got me thinking now..

I only ever notice the noise in neutral, at idle, I ?think? at standstill.. it disappears when clutch lightly pressed.. I can't remember if it does it in gear and moving! my feeling is it doesn't.. there is no wear at all on the prongs of the release arm (which I fitted new) which makes me think my idea of that slapping around at idle may be a dead end.. Jim I cant remember if the noise goes when revved..

I have recorded a video... is this just normal backlash I wonder? (assuming the video works) .. is it worth taking the end plate off and having a look inside? could this be the noise? some tests i should have done before taking it all apart seem to have been :

Grab the release arm and see if the noise abates.
Get the wheels spinning in gear (off the ground) and put into neutral and see if the noise appears when the wheels / trans stop rotating

https://photos.app.goo.gl/LK5nW79wCazyLPtg7
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Re: Hydraulic clutch question

Post by jgra1 »

whatever, I am loathe to do much except fit it all back together and enjoy the summer, the van was chugging around The Lizard a week ago! I suspected a release bearing as the obvious cause, and (thought I) had to strip it apart to check.. doh! and also wanted to look at the clutch itself anyway..

How can I lift the box half a metre back up to the engine I wonder? it's fairly heavy. In the past i have strung them to an engine crane which kinda works but the crane legs get in the way somewhat! I almost want a gearbox stand, but a tiny one ;)

edit.. the answer could be one of those small telescopic motorbike lifts with castors! I had one and sold it, typical! :rofl2:
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Re: Hydraulic clutch question

Post by mickthemaverick »

I use a pair of axle stands with a plank across them, use a trolley jack to get the box up onto the plank then put the jack under the plank and jack a hole at a time extending the axle stands as you go. Obviously you need a jack with a decent lift range!! :-D
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Re: Hydraulic clutch question

Post by mickthemaverick »

Just watched the video and that end float does look a bit iffy to me, may well be the issue you are looking for!! :)
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Re: Hydraulic clutch question

Post by Hell Razor5543 »

mickthemaverick wrote: 15 May 2023, 19:22 Obviously you need a jack with a decent lift range!! :-D
Or a brick or two to make up the difference!
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Re: Hydraulic clutch question

Post by jgra1 »

thanks Mick! what can i do tonight to prove a bearing is going? and can I do it via the end plate do you all think? (is it worth taking it off)

I have never looked inside a manual GB before :mrgreen:


I need the box back in at the weekend for sure! would be great to change something and make it better while it's out.

I have a decent long reach jack here.. and stands and wood etc.. will have a think. In the old days I would put it on my chest and manhandle it, but it's too heavy and too high and not the way anymore ;)
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Re: Hydraulic clutch question

Post by mickthemaverick »

That is a tricky one!! Proving the problem is going to need an internal inspection, ideally by a gearbox expert. If you have a transmission specialist nearby I'd take it to them to check. I certainly have no idea how you would get inside the box and then, if you do, what limits are relevant to check. I'm afraid that my internal box experience is limited to motorcycles and my Reliant!! :-D

Plus of course if you do start digging tonight and find a fault you'll still need to get the new parts before you can reassemble it. If the weekend is essential then you may find a can of worms that will not get it sorted by then so I'd put it back in as it is and then attack it when you don't have a time limit! Good luck whichever way you decide to go!! :)
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I used to ride on two wheels, but now I need all four!
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Re: Hydraulic clutch question

Post by jgra1 »

Mick, all true enough.. I will spend some time on youtube and see what that teaches me. at least if the box goes back in, I can do some more testing and prove what's up more easily. :)

I would say the noise has been getting louder over the last few thousand miles, and I am not too worried about a major failure anymore (like I was last week, with a possible bad clutch!) happy to rebuild it all and deal with it some other time..
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Re: Hydraulic clutch question

Post by jgra1 »

just an update ;)
I refitted box, went away for a weekend, and then decided to bite the bullet and bought a bearing kit and a release bearing.

Box off again!

removing the endcover off the box, and no play in the input shaft bearings.. sent the kit back, refitted box with the new release bearing and it's as noisy as ever !

My only theory is the backlash that you can hear in the video is the noise I can hear, the worst time for this is when you switch off.. clank clank.. otherwise the noise is there in neutral whenever the clutch in not engaged.. The engine doesn't rotate smoothly due to reciprocal movements, and this causes the noise ?
some of my gears must be worn out.. I suspect they will be expensive too! Will update some day in the future if I get anywhere with the old bus..

John
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Re: Hydraulic clutch question

Post by PaulC5 »

Couple of questions, how many miles has the gear box done and is there oil in it ?
I have replaced gear box bearings on a couple of high mile Saabs, both around 150k miles. On these the bearings had worn out but the symptoms were whining noises and on one (possibly the input shaft but it was around 1995), the bearing was that badly worn the shaft could move in and out enough for it to jump out of gear.

When you replace the brake fluid every 2 years the clutch fluid should also be replaced and if this has not been done you have nothing to lose by doing it. I find the clutch fluid tends to be a bit black from the cylinder seals wearing and afterwards the clutch pedal can be a bit lighter to use. Possibly this might help the slave cylinder if it is backing off from the release bearing a bit too much.