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73 Cj6 Hydraulic Clutch Conversion Issues.

Discussion in 'Intermediate CJ-5/6/7/8' started by dsrt4, May 5, 2024.

  1. May 5, 2024
    dsrt4

    dsrt4 Member

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    Oct 30, 2009
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    I swapped in a cj7 slave CS11956 and a yj master cylinder Dorman CM39644 into my 73 cj5 to cj6 project. I am using the bell housing mounting location and the rod that came with the slave. I have an adjustable rod on the master cyl at the pedal . I can bottom out the master cylinder with the pedal so it seems it is getting full throw at the pedal. The issue I am having is there just isn't quite enough throw at the slave cylinder to completely disengage the clutch Making it hard to get it into gear with the engine running. The slave rod seems to be at the correct length as is for the clutch arm.


    Any Ideas on this? The master cyl I am using says it has a .687 bore dia. Should I try a .750 dia bore master cyl? I was trying not to reinvent the wheel with the parts. I thought this is what everyone used when they pieced their own hydro kit together?
     
  2. May 6, 2024
    RATTYFLATTY

    RATTYFLATTY I think you need a little more throttle

    Central MN
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    Or maybe bigger than that, the AMC master on a 1980 CJ with the Iron Duke had a clutch master cyl with a 13/16" bore I believe.
     
    dsrt4 and Ol Fogie like this.
  3. May 6, 2024
    Rich M.

    Rich M. Shoe salesman 2024 Sponsor 2023 Sponsor 2022 Sponsor

    Maryland
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    Pictures? Is the rod from slave to fork adjustable? You need just enough clearance so the throw out bearing isn't running when the clutch is released. The average clutch needs about 5/8" travel to throw out. Most slaves only travel about 1.5". You may need an adjustable pivot ball depending on your setup. Geometry dictates you need to stay at a maximum of 2:1 ratio. Meaning the distance from the attachment of the slave at the fork to the pivot can't be more than 2x what it is from pivot to center of TO bearing.
     
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  4. May 6, 2024
    PeteL

    PeteL If it wasn't for physics, and law enforcement... 2024 Sponsor 2023 Sponsor 2022 Sponsor

    Hills of NH
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    I can't say if this is your problem, but I have always felt that my stock '88 YJ needed a larger m/c bore, to shift better.
     
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  5. May 6, 2024
    dsrt4

    dsrt4 Member

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    The slave rod to fork is not adjustable. I really didn't see that anyone had to modify the slave rod during retrofit. I may order a .875 master cylinder and see it does the trick. And at the same time see if I still have my adjustable section from the bell crank style set up.

    I'm sure I could fabricobble something up as well.
     
  6. May 6, 2024
    Rich M.

    Rich M. Shoe salesman 2024 Sponsor 2023 Sponsor 2022 Sponsor

    Maryland
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    Disconnect the rod from the fork and see how much travel the fork has before it contacts the pressure plate. It only takes a small amount of clearance when released.
     
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  7. May 7, 2024
    PeteL

    PeteL If it wasn't for physics, and law enforcement... 2024 Sponsor 2023 Sponsor 2022 Sponsor

    Hills of NH
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    "fabricobble"

    :clap:
     
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