Omega Clutch Woes

Discussion in 'Omega' started by Rich White, Sep 6, 2006.

  1. Rich White

    Rich White Guest

    I intend to post a longer message later to describe my problem, but in
    advance of that, can someone describe the mechanical layout of the
    clutch release mechanism on a 2.6V6.

    In VERY short, the problem is that what started out as a "clutch needs
    bleeding" diagnosis on my part has not been the case. Even after
    bleeding...
    Clutch doesn't come back up properly on releasing (can be popped up by
    foot) - although drive is engaged OK. Pressing accelerator (henceforth
    know as gas for ease of writing) makes clutch pedal pop up.
    See-Saw action detected - applying slight pressure to clutch pedal and
    then on and off gas causes clutch to go down (no real back pressure, it
    just drops) when lifting off gas, but clutch presses back up on
    applying gas.
    The above behaviour is detected in gear 1/2/3/5 and R, but not 4th!!
    Example :
    Go from 2nd to 3rd:
    Lift off gas / Clutch goes down a bit (as above) when slight pressure
    applied, push all the way down, and clutch engages, change to 3rd,
    release clutch (pedal doesn't return up), apply gas, pedal pops up.

    Go from 3rd to 4th
    EXACTLY the same, but on applying gas, clutch does not pop up. I can
    come on and off gas in 4th, and clutch pedal remains stuck down (about
    1 inch off floor).

    now - two interesting points from this stage:
    1) If I pop up clutch pedal with foot, and then press down again, there
    is really GOOD pressure. Nice weight, engages well etc
    2) Remember I said I can come on and off gas in 4th and pedal remains
    down. If I leave pedal alone, don't touch clutch at all, and slide in
    to 5th (let the synchromesh do the work), as soon as apply gas, pedal
    pops up. I suspect if i did the same down to 3rd (with a blip of gas
    in neutral to help), it would do the same.

    So - points of note;
    - My reference to "pop up" is the fact that the pedal is counter sprung
    - so it compresses the spring on down and up, hence the "pop" is caused
    by the pedal spring holding the pedal down, and then pulling back up
    past the mid point. My analysis though is that when the pedal sticks
    down, there must be no return pressure from the hydraulic system/cluch.
    - I HAVE bled the system completely. It just doesn't feel like a
    hydraulic problem now...If it was master cyl., then why is it PERFECT
    in 4th (good back pressure), and PERFECT when stationary with no engine
    running.
    - If it were the slave, same applies really.

    - Since it affected by on/off gas, it sounds "torsional". I have
    checked engine mounts/gearbox mounts. they are fine (the car is a 52
    plate, 110k miles). There is absolutely no drivechain noise (clonks
    etc) when coming hard on and off gas in, say 2nd.
    - There is no release bearing noise

    So, I'm guessing this must be something going on in the bellhousing
    (still don't quite understand how the gear can affect this), but since
    there are no pics in the Haynes guide of the bell housing, and the
    clutch release assy is all contained within it, with no inspection
    point, I need some idea of what this could be, or why.

    I'm more than happy to pop the gearbox out, but would ike to be armed
    with either
    clutch kit or release cyclinder assy, and not both, before I do it.

    Any thoughts would be useful. I really think I've covered everything
    (I had actually planned on this being an introductory mail to the
    problem, but it seems to have grown!!!). I'm a more than competent DIY
    mechanic and have replaced countless clutches on RWD cars.....I think
    I've seen a good number release mechanisms, cable and
    hydraulic......but this fault is stumping me. I guess it could just
    end up being cover plate springs......but why the 4th gear anonmoly!!
    ........and why would a 3.5 year old car, with 110k have a shot
    clutch......to do that mileage, generally requires lots of long trips
    (and I know it was an Exec's car, doing travelling all over the
    midlands), so it's probably done less gear changes than Mrs Housewifes
    Corsa with 12k on it.

    Help!!!

    Rich
     
    Rich White, Sep 6, 2006
    #1
  2. Rich White

    Rich White Guest

    On other thought.....no obvious leakage from base of bell housing...So
    i dont suspect oil seal/contamination, but I guess it could be.

    What's the score with a dual-mass flywheel - don't these beasts have
    one? could this be a factor?
     
    Rich White, Sep 6, 2006
    #2
  3. Rich White

    me140 Guest

    The oil filter housings get really tight - you may need to hold the main
    part with some big grips and push harder. I agree that they are a stupid
    design.
    The clutch is an interesting problem - is the return spring in correctly?
    Has it shrunk - should be 77.5 +/- 4mm untensioned. Other than that I think
    problem is in bellhousing - maybe the pressure plate isn't returning far
    enough to push clutch up.
    Have fun getting the exhausts off cos they can be a real twat!!!
     
    me140, Sep 6, 2006
    #3
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