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Intermittent - Clutch pedal sticks part-way - 2007 C6 2.2 HDI Exclusive Manual |
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Ranger12
 
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  Member No: #4492
Location: Somewhere in the darkest recesses of England |
... so my new purchase of a 2.2 HDI Exclusive Manual C6 with 137k+ miles on it, revealed an issue to me on the 80 mile drive home. The clutch feels good, the biting point feels good, then all of a sudden, after I have fully depressed the clutch pedal, it will only return an inch or so, whereby I have to use the side of my left shoe to flick it up. As soon as the pedal has returned, I have full pedal travel back, and the biting point remains in a good place, with no apparent slippages in any gear (so far). It has been suggested that this can be down to rubber-degredation in the clutch fluid, with bits in the fluid occasionally and intermittently lifting seals and causing internal fluid loss in the master cylinder. I have tried to find details of ANY operation to check, maintain, and fix the clutch systems on this car, but have failed. Even my service manual only covers the V6 2.7 Autobox. Does anyone have documentation for proceedures to check and repair this system, preferably with diagrams? Or does anyone have personal experience of fixing this particular fault? I can't even find details of how to flush/replace/top-up the clutch fluid, let alone locate where all the related parts are. I have tried following the clutch parts from the bulkhead side, but without stripping some parts, I haven't yet been able to locate the master cylinder and associated piping, and unable to find which fluid is meant to be used. Any ideas? |
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PDB
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  Member No: #2082
Location: Belgium |
Hi, my 2.2 HDI has the same problem. I looked at some French forums on 407's, more cars with 2.2 HDI and MLC6 gearbox around, more experience, same technical stuff. This can be something to do with the hydraulic part, but its very rare the problem comes and goes if it is that. If the problem is not with the "hydraulic part", they conclude it's the pedal spring that's not pulling the pedal up like it should. Most people including myself just ignore it and have driven many KM's with the issue ( mine for 25.000 now). Check the pedal spring, that's not in the books. |
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Ranger12
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Member No: #4492
Location: Somewhere in the darkest recesses of England |
Thank you for your response, that is really helpful. I was thinking I might try a bungee cord on the pedal to see if that makes for a better drive (unfortunately, mine has a habit of doing it in really dangerous situations like trying to change down gears approaching busy roundabouts on busy roads, and then not allowing me to select a gear until I have pushed the pedal up). It does seem to be a hydraulic issue, and I think it may have something to do with one of the master cylinder seals getting stuck with debris, or the return spring in the master cylinder being weak, as I have had similar happen in the past with my motorcycle front brake lever. Usually the cure is to flush the system, replace whichever rubber pipe was degraded internally, and replace the master cylinder spring and seals. Unfortunately I have not been able to get a diagram of the C6 clutch & related parts in order to even attempt this. The actual clutch pedal spring appears to be good. It has good feel when returned, and when it does so by itself, there is no evidence of it being the pedal spring, which is why I am sure it is a hydraulic related issue, most likley degraded seal/s and spring/s in the master cylinder. I was hoping someone has dealt with this before, and would know where to drain/bleed the hydraulic clutch, and even if the clutch shares fluid with the suspension system, or if it has its own circuit like the brakes? Mentioning the brakes, I just remembered that a few times as I was braking and just about to depress the clutch pedal, as I applied the brake, I also felt the clutch pedal dip fractionally under my left foot just before I depressed that. Are the clutch and brake hydraulics linked by any chance? |
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Jas16
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 Member No: #2994
Location: West London |
out of interest, was the car sitting parked for an extended period of time? the easiest would be to change the fluid otherwise maybe have someone pump the clutch and try and get a camera looking sideways to see if the clutch pedal is not catching on anything bit vague response, but trying to narrow down potential options. |
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Ranger12
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Member No: #4492
Location: Somewhere in the darkest recesses of England |
Hi Jas16, yes it seems the car was sat for some time, less than a year I think. When I bought it the pics showed a pristine car, when I went to see it, it had obviously been stood for quite some time, or barely used. Filthy inside and out and smelling strongly of wet dog. Fortunately it has cleaned up well. How do I change the fluid?, I haven't been able to locate the filler/drain - nothing about the clutch setup in my workshop manual unfortunately (only autoboxes covered even though it mentions manual gearbox). I have checked to see if the clutch pedal is sticking on something but it is clear from interference - nothing visibly getting in the way, and springs feel good. I have noted whilst driving that there appears to be a bit of movement in the gearstick, suggesting worn engine mounts, and I am wondering if they can cause the clutch mechanism to stick, as it appears to happen most often under deceleration, going down the gears. A couple of days ago I stopped at some traffic lights, put the parking brake on and put the stick out of 1st. When I went to pull off, I pushed the clutch in (which felt the right amount of resistance) but the pedal went to the floor without disengaging the clutch, meaning I couldn't select 1st gear until I had used my 'clutch' foot, to pull the lever back up. On reaplication the clutch disengaged properly, and I had gears again. It feels like a hydraulic issue, and appears to be getting worse like it was getting less and less fluid, and incidentally, the suspension has been getting a bit hard when first driving, then softens up after a few hundred yards. I think I may have small fluid leaks, so I wonder, does the clutch share the same LDS fluid source as the suspension? If they do, that would explain the degrading performance of both, if not I obviously have potentially two separate hydraulic systems to check for leaks. |
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MGmike
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   Member No: #3151
Location: South Queensferry |
I'd be surprised if the clutch uses the LDS system as that would give too many potential failure points on a "critical" system. It wouldn't, however, surprise me if the clutch shared the brake master cyl reservoir. Your traffic light experience suggests a clutch master cyl seal issue. In the absence of any info in the manual, I would remove the air filter, find the clutch slave cyl and follow the pipes back to the the master cyl. From there you should be able to follow the pipe to the fluid reservoir. |
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Ranger12
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Member No: #4492
Location: Somewhere in the darkest recesses of England |
I think you're right, and I've managed to trace the piping to an area behind aluminium thermal protection sheets, but still unable to find where whatever the right fluid should be, should go. I found the bleed nipple underneath the air box, but I can't do that if I don't know what fluid to use, or where I'm supposed to stick it (though I'm sure there'd be plenty of fun suggestions about where I can stick it).  What is throwing me is that there is one pipe coming from the gearbox bell-housing with bleed nipple, but I just can't locate a pipe coming from the Master Cylinder (because I can't see it) which goes to any resevoir, there appears to be just one pipe, and one bleed nipple. So, I am wondering if the Master Cylinder is behind the heat shields on the bulkhead, and if I need to get at it from under the car? At present I just do not have access to any work-space other than scrabbling around in the dirty gutter of a busy road, and without knowing the proceedure to do this job, that is a certain recipie for making a complete hash of this. I have found the LDS tank, brake fluid Reservoir, coolant resevoir, power steering resevoir, all easy because they are clearly marked and in plain sight. The clutch master cylinder fluid resevoir, and bleed points, are well hidden. Does it even have a resevoir? Or is it a closed circuit? I can do all the work myself, if only I can get info on what fluid, and the procedure. I have bled many hydraulic systems of many differing types, but this is a head scratcher. It must have a fluid entry point, that must either be a resevoir, or another form of filling point. I wonder if it requires special equipment. Odd that in the chapter lists in my manual, it lists manual gearbox, but getting to that page, the only info is for autoboxes. Is there a specific manual/guides for the 2.2 HDI? |
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MGmike
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Member No: #3151
Location: South Queensferry |
I'm almost certain it shares the brake fluid reservoir. Open the bleed point and give one pump to see what type of fluid comes out. I'll be astonished if it's not DOT 4 brake fluid. The master cyl will be shared across the Pug/Cit range and if you search on other models (C5, 407 etc.) you'll find something or someone somewhere who has done it. Another way to cross reference is to look up the part for the 6 and see if it's listed for other models. Try buycarparts.co.uk. or just watch this.... - Click Here - |
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Ranger12
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Member No: #4492
Location: Somewhere in the darkest recesses of England |
Now you mention it I did check for the master cylinder and found it listed second hand for Pugs/Cit C6, however, I didn't check out Pug vids because I didn't think the proceedures would be the same. In some respects this is how my other C6 ended up with C5 lower suspension arms, even after I had asked the garage to make sure they didn't fit C5 arms. I will take your advice and see if I can find a 407 vid that deals with bleeding the clutch master cylinder. *edit* oh Thank you, that's the link you posted. I suspect you are probably right about the brake fluid master cylinder resevoir feeding dot4 to both the brakes and clutch, and I will attempt to use my one-way motorcycle brake-bleeding valve to set up a one-man operation, but just a bit worried of introducing air into the system. I notice the bleed nipple is a plastic, easy turn affair, maybe it won't let air in. |
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MGmike
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Member No: #3151
Location: South Queensferry |
I fear you'll just be wasting your time! Change the master cyl and be done with it! |
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Ranger12
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Member No: #4492
Location: Somewhere in the darkest recesses of England |
Your post came in just as I was doing exactly that. Thanks for your help, and for the link to the 407 vid. £37 from ebay delivered mon-wed next week. Unlike the 407, it's not ac pipes in the way but heat shields hiding much of the pipework too. Useful video, though he didn't show which resevoir, but the job looks like I can do it from above, or maybe removing the drivers side wheel and wheel arch plastics will enable easier access? I guess as soon as I get all the heat shielding out of the way, things will become alot clearer. Thank you all, I'll let you know how it goes. |
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