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Harmonic ballancer bolt keeps backing out

Discussion in '1973-1991 K5 Blazer | Truck | Suburban' started by 77k5, Nov 20, 2000.

  1. 77k5

    77k5 Registered Member

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    It's a 350 engine and I'll hear this funny rattling, and the center bolt on the harmonic ballancer is loose. I tighten it up and it comes loose again, I'm going to put a lock washer on it, is this a bad Idea? and I've also wondered if something is really wrong any sugestions would help allot, thanx, 77k5
     
  2. keith

    keith 1/2 ton status

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  3. Grim-Reaper

    Grim-Reaper 3/4 ton status Author

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    You sure it's fully seated? does the ballancer have wobble when the engine is running? If it's not seated correctly as the engine cycles through hot and cold the ballancer could be shifting in closer to where it belongs and the bolt has not backed out. If it wobbles thats a dead givaway it's not seated. If your sure it's seated then like Keith said put some thread locker on it like locktie. Besure to clean it. Shot some Brake cleaner into the end of the crank then blow it dry with some compressed air and same with bolt. Be sure it's dry and oil free or the loctite will not work correctly.

    Diging it in the dirt with my K5's
    Grim-Reaper
    http://grimsk5s.coloradok5.com/
     
  4. Sparky

    Sparky 1/2 ton status

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    I have the same problem, but I think it is because I just put a new balancer on and it is seating itself. The bolt does not rattle loose, but every now and then I have to turn the crank over with a wrench because I have a bad spot on my fly wheel. When I do this, every time the bolt gets tighter before the engine will spin. Oh well! It works.

    sparky

    When all else fails... Check the blinker fluid.
    78 K-5
     
  5. mudfanatic

    mudfanatic 1/2 ton status

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    this could also mean that your threads in the end of the crankshaft are shot, I ended up going down to a hardware store and pucking up a grade 8 4.5" bolt (I think that it was that long) anyway it was longer than the ones that MR Gasket sold for twice the cost, it threaded into good threads and held perfectly, with a lock washer and threadlock.
    Dan

    <font color=red>get involved with land issues or lose the land</font color=red>
     

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