Here is 308 clutch adjustment page scan

Discussion in '308/328' started by AZDoug, Aug 15, 2009.

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  1. AZDoug

    AZDoug Formula 3

    Jun 17, 2009
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    #1 AZDoug, Aug 15, 2009
    Last edited by a moderator: Sep 7, 2017
  2. PittsS2APilot

    PittsS2APilot Formula Junior

    Jun 29, 2007
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    Can someone who's done this adjustment put the procedure in language the average guy can understand? :)
     
  3. miketuason

    miketuason F1 World Champ
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    Hoe do you know when your clutch need adjustment?
     
  4. PittsS2APilot

    PittsS2APilot Formula Junior

    Jun 29, 2007
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    Mine needs adjusted because the clutch is not aligned with the brake. Its too high. I don't want to "wing it" with the adjustment and those directions in the book are not too user friendly if you ask me. Thats why I would like someone to explain the procedure in clearer language.
     
  5. Martin308GTB

    Martin308GTB F1 Rookie
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    #5 Martin308GTB, Aug 18, 2009
    Last edited by a moderator: Sep 7, 2017
    Hello from Germany,

    your profile says ' '80 GTBi'. So I assume, that you have the later style clutch design like mine on my late carb GTB. That design modification caused significantly less pedal force.
    Therefore this procedure doesn't apply to your car.
    This is the later design scheme.

    Best Regards

    Martin
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  6. AZDoug

    AZDoug Formula 3

    Jun 17, 2009
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    #6 AZDoug, Aug 18, 2009
    Last edited: Aug 18, 2009
    That looks like the same basic system without the over center assist spring/retraction spring.

    Was there any particular reason the spring was eliminated? Different clutch pressure plate, say three finger vs diaphragm pressure plate? Just not needed?

    Thanks,
    Doug
     
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  8. Steve Magnusson

    Steve Magnusson F1 World Champ
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    #7 Steve Magnusson, Aug 18, 2009
    Last edited by a moderator: Sep 7, 2017
    The big change was that they went from a "non-contact" design (that needed a physical clearance between the throw-out bearing face and pressure plate when the clutch pedal was "up") to an "always-in-contact" design. Even though it is called (and is) a "helper spring", it also "drives" the throwout bearing away from the pressure plate (via the over-center action) to ensure that the clearance exists when the clutch pedal is "up".

    Here's a copy of the SB21-2:
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  9. flyngti

    flyngti Formula 3

    Jul 16, 2009
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    Steve

    If I'm reading this SB correctly, does it mean one can retrofit the later-car "less pedal pressure required" clutch to the early "need a Hercules left leg" clutch?
     
  10. Steve Magnusson

    Steve Magnusson F1 World Champ
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    #9 Steve Magnusson, Aug 20, 2009
    Last edited: Aug 20, 2009
    Yes (if you can get the pieces).
     
  11. Martin308GTB

    Martin308GTB F1 Rookie
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    I'm not Steve, but yes. If all the listed, required parts - except, like said, the clutch housing - are available.

    Best Regards from Germany

    Martin
     
  12. rcraig

    rcraig F1 Rookie

    Dec 7, 2005
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    Last page of bulletin shows great view of adjustment for new system. Does anyone have same type drawing and instructions for earlier 78-79 system?

     
  13. Steve Magnusson

    Steve Magnusson F1 World Champ
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    #12 Steve Magnusson, Aug 21, 2009
    Last edited: Aug 21, 2009
    The figure & text in post #1 (page D7 in the 308GT4 WSM) and page D6 are for the earlier system -- here it is with a little more explanation and a good photo that another FChatter posted before:
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    1. Disconnect turnbuckle 4 from arm 1 by removing the clevis pin

    2. Adjust the length of turnbuckle 2 to line up the holes in the photo (when the locknuts on the ends are loosened, and sleeve 2 is rotated, the length will change because one end is a LH thread and the other end is a RH thread)

    3. Then, with the clevis pin still removed that holds turnbuckle 4 onto arm 1, adjust the length of turnbuckle 4 so that the hole in the clevis is ~3mm (1/2 of the 6mm hole size) forward of the hole in arm 1 when lightly pushing turnbuckle 4 forward in the direction of actuation (i.e., when the throwout bearing is contacting the pressure plate).

    4. When you then reinstall the clevis pin to connect the clevis on turnbuckle 4 to arm 1, this moves the throwout bearing away from the pressure plate to the specified 2mm distance (on page D6).

    The locknuts on both turnbuckle 2 and turnbuckle 4 are of the RH and LH variety so make sure that you turn them the correct directions to loosen/tighten.
     
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  15. John M

    John M Formula Junior
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    Nov 18, 2004
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    Sorry for the old post drag out....

    Hey Steve (or any others that wish to reply)...on this service bulletin you posted....did you take note of the fork affixing bolts position before making your measurements? Note that the bolts are centered on the shaft off the vertical line in the diagram...leaving the clutch fork off its base and not fully retracted. I assume this is correct as the later clutch setup throw out bearing is constant contact. If you don't set the fork position right...you end up measuring incorrectly for the 40-45mm on the eyelet for the clutch cable.

    Essentially what I am asking here...should the fork be fully retracted for the measurements...or bolt centered as in the diagram with the fork arms off the seat? Makes a difference when you go to measure the 40-45mm. Want to make sure I do this once!:D

    Best Regards,
    John M
     
  16. Steve Magnusson

    Steve Magnusson F1 World Champ
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    #14 Steve Magnusson, Nov 12, 2011
    Last edited: Nov 12, 2011
    Don't follow your question John.

    Post #12, talking about misaligning the holes by 3 mm, is for the early design (where the throwout bearing in not in contact with the pressure plate when the clutch pedal is "up") -- there is no "40-45mm" spec involved with this early design.

    The figure in post #5, with the 40-45mm dimension, is for the later design (where the throwout bearing is always in contact with the pressure plate) -- there is no need to remove any of the clevis pins when adjusting this late design.

    Which design are you dealing with? early or late?
     
  17. John M

    John M Formula Junior
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    #15 John M, Nov 12, 2011
    Last edited by a moderator: Sep 7, 2017
    Hi Steve:

    Dealing with the later style and the SB21-2 you posted. This is the constant contact type. Looking at the last diagram on the last page.

    When you look at the diagram, it shows the fork on the shaft that runs down to the lever. The control rod (labeled #6) connects to this lever/shaft assembly that moves the fork. My question is do you align the fork as pictured? Those two bolts are depicted in the diagram as centered along the shaft, facing 90 degrees up. This leaves the fork not fully retracted against the bell housing to make these measurements. Is this correct? If you fully retract the fork against the bell housing leaving the studs off center, this totally changes the measurement when you go to get the 40-45mm alignment for the clutch cable. You end up having to lengthen the control rod well beyond 105mm to get the alignment for the clutch cable eyelet.

    So fork as pictured in the diagram with the bolts on center....or forks fully retracted? I did the measurement on center for the fork bolts. Pic attached. And thanks for the help!

    Best Regards,
    John M
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  18. Steve Magnusson

    Steve Magnusson F1 World Champ
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    #16 Steve Magnusson, Nov 12, 2011
    Last edited: Nov 12, 2011
    Neither (although "bolts on center" might be fairly close, and it defintely isn't having the forks fully retracted into contact with the bell housing). The 40-45mm applies when the fork ends are in (gentle) contact with the throwout bearing under the slight pressure from the extension spring at the clutch pedal that puts a little tension on the clutch cable when the clutch pedal is full "up". It's not something that you can "set" precisely when the bell housing is not mounted to the engine.
     
  19. John M

    John M Formula Junior
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    Got it Steve. Set the rod to 105mm...assemble the bell housing on clutch....then measure the 40-45mm once all hooked up. Thanks for the Saturday night reply! Now off to get'r done.

    Best Regards,
    John M
     
  20. david

    david Formula Junior

    Feb 21, 2001
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    Resurrecting this thread. I have a fairly new clutch in my 77 308. It has maybe 5 or 6k miles on it since it was installed. One thing that I don't like is that I don't have a lot of pedal travel before the clutch engages. The pedal position is proper, i.e. it is even with the brake pedal. But it seems to me that I should have a bit more travel between when the pedal is pushed all the way in to disengage the clutch and the point at which I first start to engage the clutch. (I hope that is somewhat clear.)

    After reading some of the description on this thread and then some other descriptions about cable adjustment, I am not really sure what I am supposed to adjust. Can anyone point me in the right direction? And also correct me if I'm wrong and this isn't a problem. I'm worried about nicking a gear tooth or something if there is so little difference between engaged and disengaged. I'm used to the way things work right now, but I'm just not sure that it is correct.
     
  21. George Vosburgh

    George Vosburgh Formula 3
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    May 26, 2011
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    Pittsburgh, PA
    Has anyone out there actually replaced an early clutch with the more "user friendly" later clutch???
     

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