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Thread: Clutch not disengaging

  1. #1
    Guest Amoeba's Avatar
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    Clutch not disengaging

    For a few months now my clutch has been catching ever so slightly with the pedal fully depressed. Foolishly I've not done anything about it until today when it decides to catch, let's say, 'more significantly'

    So I've bled the clutch from the 3 nipples (master / slave / weird pipe thing) but the same still happens. Interestingly a lot of gunk came out of the weird pipe thing, so I'm wondering if some rubber has perished somewhere. However the levels were fine in the master cylinder with no evidence of leakage anywhere and regardless, the clutch feels the same now as it did before.

    The lever going into the bell housing appears to operate smoothly, although I would say the slave cylinder is only operating it for about half of it's travel.

    So what could it be? I've had the same clutch in for I think 4 years now, an ACT HD with Streetlite flywheel and never had any issue until recently..

    Any advice appreciated, including how to get the car into first gear from a standstill

  2. #2
    Guest Amoeba's Avatar
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    Think I will fit a new master cylinder and braided lines...

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    Bod Jon's Avatar
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    Well, neither master or slave cylinders on an S14 could be described as unreliable, but I would strongly suggest fitting a braided line directly between master and slave first, bypassing the U-Tube damper. That makes bleeding a much easier task.

    Your description of 'catching' makes me think to blame the slave cylinder rather than the master. Only reason is I've replaced the slave cylinder twice, and am on original master cylinder, at over 200,000miles total.

    Catching, in my case, meant the pedal not always springing back fully and having the compress the carpet to get clutch release, where that normally happens in the first 50mm of pedal travel.

  4. #4
    Guest Amoeba's Avatar
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    By catching I meant the clutch is catching on the flywheel even with the pedal mashed into the floor. I assume the pedal is springing all the way back, it certainly feels like it is to my foot at least

    The thing that made me wonder about the master cylinder over the slave is the reservoir was filled quite a way above the max mark, but unfortunately I have never noticed this before so can't say if it has always been that way or not. If the slave cylinder was going would I not see some leakage, or at least a lower fluid level in the reservoir?

    If not the hydraulics then what else should I be thinking of? I will try and peer through the dust boot for the fork to see if I can see anything bent or broken, but in my mind I would have thought anything of that nature would be a more 'catastrophic' failure than just making the bite point a bit low

    Anyway I will order the braided hose tomorrow and fit that to see where I stand..

    Thanks!

  5. #5
    Guest Amoeba's Avatar
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    By the way, what sort of travel should I be seeing on the slave cylinder push rod??

  6. #6
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    My bet would be a broken lever arm pivot. They fatigue over time but will stay in position until a jolt causes it to separate. Then it depends on how it lands as to whether the clutch partly operates or doesn't operate at all.

    Grab the lever arm and see if you can easily twist or move it in/out.

    The lever arm attaches to the pivot which screws into the main housing so if you can twist/push-pull the lever arm that indicates that the pivot has snapped.

    Its a 5 part but you need to take the 'box off the change it.

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    Guest Amoeba's Avatar
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    Ok so, took the dust boot off and peered inside. Couldn't see anything amiss and the lever was solid as a rock..

    Think I will replace the hydraulics (including the bypass pipe thing) and see where I land after that. Given the high fluid level in the master cylinder and the crap that came out when bleeding I hope I will see some sort of improvement..

  8. #8
    Bod Jon's Avatar
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    I never have really understood why the U-Tube damper is a problem for SXOC purposes. In theory it looks fine.

    I followed old skool SXOC wisdom and bypassed it with a flexi hose from master to slave cylinder, and have had no real trouble since then (some years ago). Fine for me.

    It bugs me that I don't know why the U-Tube is considered a problem, and why new clutch problems keep cropping up.

  9. #9
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    Its just not worth the aggro. The damper makes only a very minor difference to the feel of the pedal when the system is bled properly yet it increases the difficulty of bleeding exponentially.

    The damper just makes things harder as bubbles like to rise and don't really like to flow through narrow areas on the flat (which is what the damper is).

    Removing it makes very little difference to the feel of the pedal but because the replacement is a braided hose with a near vertical run along most of its length, its a doddle to bleed without any special kit.

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    Guest Amoeba's Avatar
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    Ok so I've replaced all the hydraulics now and re-adjusted the pedal. Was ok for 24 hours but seems to be catching again now..

    Strange thing is, the clutch isn't fully engaged until the pedal is near the top of the travel, yet is catching a little even when fully depressed.

    Any thoughts on where I should go from here??

  11. #11
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    HAve you replaced the master cylinder seals ? If so maybe its,a bent lever arm. It can happen with an upgraded release plate

    sent from t'internet

  12. #12
    Guest Amoeba's Avatar
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    I replaced the entire master cylinder

    I might take it to a garage and get them to drop the gearbox and have a look inside, it's a bit beyond my capabilities on the driveway

  13. #13
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    They should be able to do a box off pivot change and back together in 1.5 hours. Steve did that for me

    sent from t'internet

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    Home Counties Rep LED sandwich's Avatar
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    are you sure its all still bled right, if you pull the rubber boot you can wiggle the arm and see if the pivot is still in place.
    Quote Originally Posted by TheBigShow View Post
    Reach arounds are more my thing, I don't like the taste...

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    Quote Originally Posted by LED sandwich View Post
    are you sure its all still bled right, if you pull the rubber boot you can wiggle the arm and see if the pivot is still in place.
    From post 7, I think he's already done that, Aaron.

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    Guest Amoeba's Avatar
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    Seems like it's bled ok to me.. and the pedal is rock solid now too.

    The arm wiggle is minimal and I tried to look inside the clutch housing with a little torch and didn't see anything out of the ordinary. All a bit of a mystery to be honest!

    Going to give DCMS a call later I think

  17. #17
    Engine Builder Mark's Avatar
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    You sure the clutch just isnt worn out

    Does it slip at all when its warmed up?
    Quote Originally Posted by silverzx View Post
    I like Mark, he seems fair.
    Quote Originally Posted by Slip_n_slide View Post
    Mark is right.

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    Quote Originally Posted by Mark View Post
    You sure the clutch just isnt worn out

    Does it slip at all when its warmed up?
    lol. Talking of missing the obvious...When the clutch wore out on our Subaru it didn't slip either, it just became grabby and would bite fairly close to the top of the pedal...kind of like the OP describes.

  19. #19
    Guest immy21's Avatar
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    I had something very smiler which I fixed while waiting on a new slave, I didn't really need the new slave.
    Unbolt the slave, pump the clutch till the end pops out. Clean the sludge out of the rubber seal, refit, rebleed, hope for the best then repost.

  20. #20
    Guest Amoeba's Avatar
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    Quote Originally Posted by Mark View Post
    You sure the clutch just isnt worn out

    Does it slip at all when its warmed up?
    Quote Originally Posted by Jonny Wilkinson View Post
    lol. Talking of missing the obvious...When the clutch wore out on our Subaru it didn't slip either, it just became grabby and would bite fairly close to the top of the pedal...kind of like the OP describes.
    Of course this could be the problem.. haha. It's not slipping at all and before I fettled the hydraulics, it was fully biting very close to the bottom of the pedal travel..
    Quote Originally Posted by immy21 View Post
    I had something very smiler which I fixed while waiting on a new slave, I didn't really need the new slave.
    Unbolt the slave, pump the clutch till the end pops out. Clean the sludge out of the rubber seal, refit, rebleed, hope for the best then repost.
    Replaced slave cylinder, same shindig. No amount of hoping will help me now

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