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Thread: Swapped clutch.... no engagement!

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    Registered User metalmonkey47's Avatar
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    Default Swapped clutch.... no engagement!

    Hey guys, just swapped the clutch on my '70 240 and I'm having issues getting into gear. Let me start by telling you what I've done:

    Master Cylinder and Slave Cylinder are both literally brand new. Less then 4000 miles on both, and no leakage.

    I swapped the blown out clutch disk with a spare 225mm clutch disk from my Datto truck. Bother were identical. The PP was quite different so I opted not to change that since I'll be pulling the L24 for an L28 in the future and I'll be using a different clutch.

    I've got my master cylinder and slave cylinder adjustments maxed out. I 'appear' to have full clutch arm movement, but it seems I may have a dead spot in the pedal. I've bled a large amount of fluid through the slave and gotten NO air out of it.

    Where do I start????

  2. #2
    Registered User EuroDat's Avatar
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    Are you using the slave cylinder with the return spring? If so, you probably need to adjust it for the "new" disc.

    When the clutch disc wears, it moves the clutch fork towards the slave cylinder and the push rod need the be adjusted accordingly to fully engage the clutch.
    The new disc will move the fork away from the slave cylinder, but the spring on the slave cylinder will pull it back. the throw out bearing is probably some distance off the pressure plate fingers. You can check this by removing the spring and checking how far you can move the clutch fork.

    Adjustment:
    1.5 turns on the adjusting nut is 2mm on the throw out bearing to pressure plate distance.
    The correct adjustment is to screw the adjusting nut until the throw out bearing contacts pressure plate and then turn back 1.5 turns which will give you 2mm clearance at the pressure plate.
    Chas
    Chas
    5/77 280Z HLS30 403100 with some modifications
    Original colour: 305 Light Blue. The PO changed it to Red

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    Registered User metalmonkey47's Avatar
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    Quote Originally Posted by EuroDat View Post
    Are you using the slave cylinder with the return spring? If so, you probably need to adjust it for the "new" disc.

    When the clutch disc wears, it moves the clutch fork towards the slave cylinder and the push rod need the be adjusted accordingly to fully engage the clutch.
    The new disc will move the fork away from the slave cylinder, but the spring on the slave cylinder will pull it back. the throw out bearing is probably some distance off the pressure plate fingers. You can check this by removing the spring and checking how far you can move the clutch fork.

    Adjustment:
    1.5 turns on the adjusting nut is 2mm on the throw out bearing to pressure plate distance.
    The correct adjustment is to screw the adjusting nut until the throw out bearing contacts pressure plate and then turn back 1.5 turns which will give you 2mm clearance at the pressure plate.
    Chas
    No return spring on mine. Strange issue I'm having with the adjustment is that I can turn the slave cylinder adjustment rod and have literally NO movement of the clutch arm. It's like it's pushing the piston back, instead of the arm forwards.

    Sounds like air in the clutch correct? The air would be compressed before the fluid would create enough pressure to push the clutch arm, resulting in loss of movement and possibly, the ability to adjust?

    I actually was able to adjust the OLD clutch before the trans was out... now with the new trans in, I can't get the damn thing to adjust...



    EDIT: To be honest, now that I think about it I've had the master adjustments literally about maxed out since I put it on. Is there any possibility that I still have air trapped in the master, and the new clutch disk (being thicker) would require more motion from the clutch?
    Last edited by metalmonkey47; 09-17-2014 at 02:03 PM.

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    Registered User metalmonkey47's Avatar
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    Also, does the piston in the slave have to be bottomed in the bore to adjust?

    I can spin my adjustment nut ALL day and not get anywhere...

  5. #5
    Registered User metalmonkey47's Avatar
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    GOT IT. Turns out, the damn master cylinder push rod was too short. Swung by the parts store to swap it for another (assuming it was possibly leaking) and realized the new one had about 1 1/2'' longer pushrod.


    Autoparts store FAIL.

  6. #6
    Registered User EuroDat's Avatar
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    Quote Originally Posted by metalmonkey47 View Post
    Also, does the piston in the slave have to be bottomed in the bore to adjust?

    I can spin my adjustment nut ALL day and not get anywhere...
    For reference:
    The slave piston should be bottomed out when adjusting the push rod. The return spring will bottom it out when it returns and releases the throw out bearing from the pressure plate. They changed the push rod design to a non adjustable system in July 72. That system should not bottom out and should have about 5mm free piston travel in the slave depending in clutch wear.

    Quote Originally Posted by metalmonkey47 View Post
    GOT IT. Turns out, the damn master cylinder push rod was too short. Swung by the parts store to swap it for another (assuming it was possibly leaking) and realized the new one had about 1 1/2'' longer pushrod.
    Good to hear it was an easy fix. Im suprised the system could disengage the clutch when the old clutch disc was in it.
    The old disc must have been very worn to help compensate for the shorter travel in the MC.

    Thats becoming more of a problem with parts stores these days. They are not experienced in these older cars. The clutch MC is used on various vehicles, but then with different length push rods.

    Chas
    Chas
    5/77 280Z HLS30 403100 with some modifications
    Original colour: 305 Light Blue. The PO changed it to Red

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