Clutch Master Cylinder replacement

Discussion in 'Engine' started by Sp!ke, Aug 16, 2008.

  1. Sp!ke

    Sp!ke Administrator Staff Member

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    Unusually, my W124CE has a manual transmission.

    Recently my clutch pedal has been feeling very odd and in the last few days it was almost not disengaging at all.

    So today I went about changing the clutch master cylinder which is situated up near the pedals held tightly up against the steering column.

    The Haynes manual said undo the two bolts, remove the circlip pull it out and swap with new and then bleed the system - easy. :rolleyes:

    This turned out to be a an absolute pig of a job. Working upside down in the footwell with absolutely no room to manoeuvre (next time I'll remove the seat for better access) and no possibility of any of my tools managing to reach the two bolts holding the master cylinder in place, there was nothing to it but to completely remove the whole pedal assembly for both the brake and clutch. Hoses removed, fluid everywhere (including inside my ears), skinned knuckles on each and every digit on both hands and much swearing and cursing throughout. :crazy:

    The reverse of the procedure clearly required special Mercedes grown midgets, bred with peculiarly small hands (three of them too). Much patience was required, especially trying to put back on the hoses with no slack whilst upside down with a torch in my mouth (and a disturbing burning sensation in my left ear).

    So on to bleeding the clutch...

    I opened the Haynes book once again and they now say you should use a certain Mercedes pressurised tool to bleed the system properly. It also says you need an assistant - neither of course I had access to at that moment. :( Since the car cannot be moved until the clutch actually works, its not like I have the luxury of waiting until one of my ever so busy friends takes pity on my and offers to assist either.

    So with the car up on stands, I manage to find the slave cylinder tucked up on the rhs bellhousing. Working alone, there was nothing else to do but chop a length of wood to size so as to be able to wedge the clutch in its down position, then climb under the car, release and re-tighten the bleed nipple before clambering back out from under the car to remove the home made wedge, release the clutch pedal before starting the process all over again and again and again. 75 times to be precise.

    I'm now absolutely knackered. The clutch is now behaving as it should (despite not having the Mercedes special tool) but I still have the whole middle and lower section of the dash to put back in and bleed the brakes but I'm so exhausted, I just can't face it hence coming on here for a rant.

    I feel much better now for doing so. Anyone else ever had similar pig jobs on their cars?


    p.s. I wonder what the book time is for replacing the master cylinder? Whatever it is, its probably worth it.
     
    Last edited: Aug 16, 2008
  2. Dieselman

    Dieselman Banned

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    This thread is no good without pictures....;)

    You could probably have bled the clutch by gravity only.
     
  3. OP
    OP
    Sp!ke

    Sp!ke Administrator Staff Member

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    All done and dusted, brakes were easy thanks to my Mityvac (which I couldnt fit on the clutch slave).

    Car taken for a spin and its clear that my clutch has been rather unwell for a while and it'll take a few days for me to get used to it biting in the correct position.

    Rather odd I thought that the brake fluid resevoir is shared for the clutch.

    I'm a happy bunny with skinned knuckles and an itchy ear now, having saved a fair bit of money on the job. :D

    I'm guessing that it would be a couple of hours labour time even for a pro.
     
  4. Ian B Walker

    Ian B Walker MB Club Veteran

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    Take a rubber hose and connect it to the front brake calliper bleed screw. Connect other end to clutch cylinder bleed screw. Open both bleed screws and press brake a number of times. Clutch bled.
     
  5. OP
    OP
    Sp!ke

    Sp!ke Administrator Staff Member

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    Stop it, just stop right, I simply don't want to know now. [fingers in ears la la la la la] :D

    Actually I used to have an industrial sized 250ml syringe that is ideal for applications like this, (Just pump from the bottom up) the problem is it has vanished and now I cant seem to find one of this size anywhere. The biggest I've found is 30ml or something.

    Anyone know where to buy a mahoosive syringe?
     
  6. jaymanek

    jaymanek Authorised Forum Sponsor Authorised Forum Sponsor

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    the vac thing is just a pressure bleeder.. i bought one for around £10, it just connects up to the tyre valve...

    well done though mate.. i wouldnt have tried to do it alone though!
     

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