Reuse of Certain "One Time Use" or TTY Fasteners: OK or Not?

Discussion in 'Boss 302 and S197 Technical Forum' started by dabossinnne, Apr 1, 2013.

  1. dabossinnne

    dabossinnne TMO Addict

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    Will be doing some rear suspension mods soon. From what I've read it appears that most of the critical fasteners in both the front and rear suspension (LCAs, UCA, panhard, swaybar, etc) are "one time use" or TTY-type, and should not be retightened or reused if removed.

    Although a PITA to have to do, seems to me to be relatively cheap insurance against potential catastrophic part failure. Or, are there certain "one time use" fasteners that are really ok to re-use? What say you...?
     
  2. 2012YellowBoss

    2012YellowBoss TMO Addict

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    I replace them myself. I think they would work again, for example you are at the track and do work without the correct bolts. However there is the possibility for a catastrophe failure by using the same bolts but why take the chance when you do not have to?

    If I had to guess I assume the one time use has to do with proper torque, the bolts may stretch being torqued.
     
  3. sadil

    sadil TMO Race

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    I would never re-use them. Basic materials science shows that @ yield there is already considerable plastic deformation, which cannot be reversed when the bolt is removed. Upon re-install, you are basically using a different bolt. Of course, it may and probably will hold up, but it just aint worth it.
     
  4. NewBossowner

    NewBossowner TMO Race

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    A lot of the new fasteners are torque to yield spec. They physically stretch the bolts when they are torqued to the proper spec. They are not reuseable.
     
  5. Grant 302

    Grant 302 OPM Spent: $665,833 Moderator

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    It's my opinion that some are confusing the recent designation by Ford of certain suspension fasteners as 'one time use' to be equal to TTY. I have not encountered a single TTY bolt in any Ford that was *not* in the engine. But that's just my personal experience.

    I do believe that the confusion is that some 'one time use' fasteners are designated that way due to pre-applied thread locker. If you are not using or re-applying thread sealant to bolts that were originally installed that way, then using new replacement fasteners is the way to go. Otherwise, I think you are okay if the threads are in good condition and you clean the threads and use the appropriate thread locker.

    TTY bolts use a torquing procedure and don't have a 'single' torque spec. Just sayin' :)
     
  6. steveespo

    steveespo Lord knows I'm a Voodoo Child Moderator

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    Some good fastener information here
    https://www.liberty.k12.mo.us/hs/libertyrobotics/media/massivemini/docs/MassiveMiniFasteners.ppt

    I too don't believe the suspension fasteners are TTY but some seem to use deformed flag nuts to hold torque and others use locktite. I replaced all of my rear suspension bolts and my front strut and brake caliper bolts too. These fasteners had seen 2 or more removal replacement cycles and I did it for preventative maintenance.
    TTY bolts usually have a low placement torque setting and then an angle turn to set final value, none of the suspension bolts call out this method of tightening.
    Steve
     
  7. Justin

    Justin Save the dawn for your dishes!!!

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    FWIW I have reused every single bolt in the rear suspension on this car and my 06 with no bad side effects. Also have reused them on the front suspension on the 06 and had no adverse side effects. they held up just fine for years.
     
  8. Tob

    Tob TMO Race

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    I agree with your opinion.

    I've noticed numerous times the same situation in the service manual and come to the same conclusion. When swapping in a '13 GT500 CF shaft into my '09 I was again going through the manual and came across yet another example. Note the text after #8...

    [​IMG]
     
  9. Grant 302

    Grant 302 OPM Spent: $665,833 Moderator

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    Thanks for putting that up Tob...I usually feel like I'm in the (unpopular) minority when I open my mouth about this. I'm guessing that Ford has had too many issues with people or even techs that don't follow 'best practices'. So they tightened up their liability by calling everything 'one time use'. CYA all the way.
     
  10. 2012Boss302

    2012Boss302 TMO Addict

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    Typically TTY bolts will have a torque spec like this for the heads:

    •Stage 1: Tighten to 25 Nm (18 lb-ft).
    •Stage 2: Tighten to 40 Nm (30 lb-ft).
    •Stage 3: Tighten an additional 90 degrees.
    •Stage 4: Tighten an additional 90 degrees.

    Note the two angle readings.

    I think Ford's rational is that most bolts have factory applied thread locker. When those bolts are loosened the thread locker goes away.

    Depending on the bolt I use Red or Blue Loctite.
     
  11. dabossinnne

    dabossinnne TMO Addict

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    Good info.... Thanks all for your responses.
     
  12. ford20

    ford20 TMO Addict

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    The bolts are cheap enough anyway, so why not just buy new ones? Like Justin had said a couple of guys including himself has reused the bolts before but like Grant and Tob had pointed out the bolts from the factory have some sort of locctite on them so if you do use the bolts again make sure you reapply some loctite to the bolts. But I would definitely replace all TTY bolts and follow the proper specifcations for torqueing them.
     

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