07 STI Clutch slips excessively even under light acceleration

Discussion in 'Modifications And Maintenance' started by STi Scott, Apr 7, 2013.

  1. STi Scott
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    STi Scott Well-Known Member

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    I just finished a complete engine rebuild that I performed myself, and now the clutch slips very excessively (Disappointing to say the least after this long rebuild project, but at least the engine seems to run great!). Before the tear down I thought the clutch held well, and the car drove well. I cleaned the clutch while I had it out just with compressed air and some paper towels, but I didn't use any chemicals as I didn't want to leave any residue on the clutch surfaces. Just figured getting the dust out couldn't hurt. Now it is almost not driveable. Even at half throttle the clutch will slip like crazy... I can't get into boost at all.

    I think I may have installed the clutch fork wrong initially, but I fixed that.

    I'm thinking the problem could be one of the following...
    1. The clutch fork being installed wrong initially caused excessive slippage by not allowing full clamp force, and I may have glazed the clutch on my first test spin around the block?
    2. I did something wrong installing the clutch itself?
    3. The clutch is just plain wore out... seems odd since it worked fine before the tear down though?
    4. Something broke during the install and I didn't realize it?

    What do you guys think?
     
  2. STi Scott
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    STi Scott Well-Known Member

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    Bump for some ideas before I spend the $ for a new clutch
     
  3. Mr.Tran
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    Mr.Tran Well-Known Member

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    If your able, I'd open it up again before ordering anything. Maybe see if someone can take a look.
     
  4. MNBD
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    MNBD Member

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    What kind of clutch are we talking about? (Brand, model) How many miles were on the clutch before you took it out? If you opened up the clutch hydraulic system for anything you'll have to bleed the air out.
     
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  5. STi Scott
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    STi Scott Well-Known Member

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    As it turns out the pressure plate wasn't torqued down. I installed the pressure plate flush and torqued it the first time I installed it, but I realized I had forgotten to align the clutch disc and it was off center. So I took it apart, aligned it and I guess I forgot to retorque the bolts when I put it back together the second time. All of the bolts were snugged just enough to flatten the lock washers, but not enough to bring it flush to the flywheel. Thankfully none of the screws fell out of the flywheel.

    And to anyone wondering... the pressure plate bolts can be tightened with an open end wrench through the starter hole in the bell housing. Didn't even have to drop out the trans. Of course I wasn't able to torque it to spec with an open ended wrench, but hey tight is tight right?
     
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  6. MNBD
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    MNBD Member

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    At least it was something simple!

    I am always weary of tightening bolts down without a torque wrench. Especially on something that has to withstand heavy load changes. But like you said, in the end, tight is tight.
     
    knaacker likes this.