Clutch Pedal Chatter

Discussion in 'SVT Tech Forum' started by Sara, Dec 14, 2003.


  1. Sara

    Sara New Member

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    I just put in a SPEC stage 2 clutch. I had the fly wheel machined, new pilot bearing, and throw out bearing. When accelerating through about 2800 RPMs if my foot is lightly resting on the clutch there is a significant "chatter" in the pedal.

    does anyone have any idea what could be causing this? I have only put about 80 miles on the new clutch, it is by no means broken in.

    Is there a way to adjust the pedal?

    1999 Stock Cobra
    #1
  2. missouri_guy197

    missouri_guy197 New Member

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    You can pull up on the clutch pedal until it clicks...the stock quadrant has a self adjuster built in, albeit not a very good one since it's plastic...another solution is to get a UPR or Steeda quadrant and firewall adjuster...

    BTW...my SPEC Stage II chatters a little, esp if I'm in 5th and I'm at a low speed...
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  3. isdnmatt

    isdnmatt Founding Member

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    I also had the chatter. It was quite bad when i started at low RPMs early on. Had to rev a little higher to avoid the chatter until it was good and broken in. Sometimes it'll vibe the pedal slightly, comes and goes for me. Pulling up on the pedal should help too.

    Matt
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  4. stock SVT

    stock SVT New Member

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    Welcome to my world

    Oh yes, the infamous chatter. My Stage 2 has barely 1,000 miles on it and I broke it in up to almost 800 miles. Treated it very nicelike. The bad thing about this clutch that I am noticing is the same chatter and pedal vibration. I have tried pulling up and resetting the pedal but it still does it. The only thing I have found that helps is to apply a bit, and i mean a little bit of tension with a pry bar on the clutch fork and then reset the clutch. It cures it until... I side step the clutch or do anything where the pedal slams to the top. Then it is back to square one. So I went and bought a steeda firewall adjuster and will have to break down and install it.


    I also called the Spec number that came with the clutch and they told me it was perfectly normal until a little over 1,000 miles. If it continues I am supposed to call them back. But the firewall adjuster will fix it.


    Greg
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  5. isdnmatt

    isdnmatt Founding Member

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    I have the Steeda quadrant and adjuster. It doesn't really help the vibration. It will just let you adjust the pedal so that it always has a little additional tension.

    Matt
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  6. fiveofanatic

    fiveofanatic How to fuel a Mustang: Founding Member

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    In my experience, clutch chatter was most often related to not torquing the clutch assembly onto the flywheel properly; how careful I was when tightening the clutch disc/pressure plate assembly onto the flywheel always made a difference.
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  7. Thunder5.0

    Thunder5.0 New Member

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    I just put in a HD Ram Kevlar kit in my Cobra. I also have a very faint chatter when I hit the gas and take off in first. If I release the clutch with no gas, there is no chatter.
    Nonetheless, this clutch shifts nicely at 6800. Great mod.
    #7
  8. Craig Mack

    Craig Mack Busted Buffing the Bishop Founding Member

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    I just got a SPEC stage I clutch put in 250 miles ago. I have this chatter too. At low rpm cruising, the clutch pedal vibrates harshly sometimes . Sometimes at idle, I will here a fast paced "thud-thud-thud-thud" coming from the chattering clutch. If I depress the clutch just SLIGHTLY, the noise goes away and everything is smooth. The fact that the chatter goes away when I push in the clutch means that mechanically i'm sitting pretty.

    I also got a burning smell that just seems to be going away. I called spec, and they said it's normal since the clutch is made mostly of metal and kevlar. He said the chatter could be from a unevenly surfaced flywheel, that even if the resurfacing is .005 off from perfect, it could cause some shutter. The flywheel was resurfaced on a machine precisely though, so I doubt it's that. My tranny guy says it could just be the fact that it's a high performance clutch matched with the stangs cable driven mechanical system, and if it was hydrolic it would cure the vibration.

    I have accepted the clutch chatter for now, as it's not really that bad, and since it isn't hurting anything mechanically. It's good to know that i'm not in this boat alone though!

    -'97 Cobra, rebuilt tranny at 46k, spec I clutch, resurf fly.
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  9. stock SVT

    stock SVT New Member

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    I have (temporarly) decided to just re-adjust my pedal by applying very slight tension onto the shift fork and then resetting the pedal. It makes it all better until I side step power shift. But it keeps me good to the car until I go with some sort of adjustable cable or quadrant.
    #9
  10. Lo Pony

    Lo Pony Founding Member

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    The chatter you're describing is the throwout bearing rotating against the pressure plate fingers. This isn't "clutch chatter", since clutch chatter refers to the grab/release/grab when engaging the clutch from a stop. Thus, what you're describing is more of a "vibration" of the clutch pedal. The only way to get rid of this problem is to get a firewall adjuster and adjustable quadrant to allow the throwout bearing to pull back away from the pressure plate when the clutch is engaged. Believe me, it will save you headaches later, since a t/o bearing partially against the pressure plate will cause the bearing to wear out prematurely. You can also fabricate a return spring to pull the release lever back and allow the t/o bearing to remain stationary when the clutch is engaged. TxSnakeCharmer has a good writeup on this little procedure on his website. I did it to my car and it is satisfactorily effective.

    http://www.shane.roberts.net/quad.htm
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  11. Craig Mack

    Craig Mack Busted Buffing the Bishop Founding Member

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    :bang: How prematurely will it wear out? I can't afford to have my tranny opened up again and messed with.
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  12. Lo Pony

    Lo Pony Founding Member

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    I put a new t/o bearing in to remedy this very problem and I only went another 7-8k miles before it got so irritating I had to replace the whole clutch. The problem is due to either bent/uneven pressure plate fingers, which can be caused by tightening the pressure plate unevenly when installing (improper torque pattern). My advice would be to get a firewall adjuster and quadrant from UPR (get the new blue firewall adjuster), and install a return spring on the release fork. This will let your t/o bearing live a long time, and you won't have to deal with the pedal vibration when the clutch is out. :)
    #12
  13. missouri_guy197

    missouri_guy197 New Member

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    Hmmm...I might have to try Shane's mod...My pedal vibrates so bad sometimes that its audible with the stereo on...
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  14. Craig Mack

    Craig Mack Busted Buffing the Bishop Founding Member

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    What you just described sounds very accurate to what my tranny guy was saying, I am pretty sure you nailed it.

    Unfortunately there is no way I can afford to buy this mod, open the tranny back up,and have them install it. :bang: How long can my throwout bearing last under my current circumstances? I can live with the vibration just as long as I know mechanically i'm doing ok. I'll tell you what though, the chatter from the clutch pedal does get on my nerves sometimes, but even softly turned up music will cure that.

    Looks like we all got :owned: by our installer or whomever else...
    #14
  15. Lo Pony

    Lo Pony Founding Member

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    The firewall adjuster is about 40 bucks, and the quadrant about 30 from UPR performance products. They're not too bad to install...if you can do spark plugs, you can manage these two items, and that should take care of your problem.
    #15
  16. jerry beach

    jerry beach Founding Member

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    You dont have to open your tranny up, or even take it out to fab up a return spring like that. Follow the instrutions on the link. Its a cheap fix and its worth a shot. I thought about doing it to mine, but I have no chatter or vibes. And I have the FWA, nice.
    #16

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