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Stihl MS250 loose bar bolt

Discussion in 'Mechanic and Repair' started by mtpisgah, Sep 26, 2009.

  1. mtpisgah

    mtpisgah LawnSite Member
    Posts: 11

    I have a three year old Stihl MS250 and have never had any problems with it until today. After I changed the chain, the forward most bar nut would not tighten like the rearmost would. I noticed that the bolt that is mounted in the housing was turning with the nut after a certain point. I had never noticed it as a problem before when adjusting the tension.

    Is it supposed to do this to keep you from tightening it too much?

    The bar only loosened once during three more hours of heavy cutting so the saw didn't let me down.
  2. Breezmeister

    Breezmeister LawnSite Bronze Member
    Male, from South Jersey
    Posts: 1,546

    No, Keep an eye on it if you are going to use it like it is, you should get it fixed asap,
  3. ricky86

    ricky86 LawnSite Bronze Member
    Posts: 1,841

    There is an oversize bar stud available. You get one chance to install it correctly. Part number 1123 664 2405. Using the saw with one stud is not a good idea.
  4. mtpisgah

    mtpisgah LawnSite Member
    Posts: 11

    Ok, I will not use it again until it is fixed. I am fairly mechanically inclined, is it easy to replace the stud? Any guess as to why it stripped? Does this happen often? Why do I get one chance to install the oversized stud? Is it tapping the old hole?

    My MS361 should be here tomorrow so if I need a saw before I get the 250 fixed, I can use it.
  5. ricky86

    ricky86 LawnSite Bronze Member
    Posts: 1,841

    Yes, it's easy. If the old stud is out, the replacement will start in the existing hole. No need to drill. Red Loctite is recommended. Use the 2 nut method for installation (and removal of the old if necessary). It was overtightened at some point. Yes. whenever they are overtightened. Once you displace the material, you can't put it back. No, it's not tapping the old hole. The thread design is called thread forming. It sort of moves the material. It doesn't remove it like a tap. Once you use the 361, I doubt the 250 will be used again - ever.
  6. mtpisgah

    mtpisgah LawnSite Member
    Posts: 11

    Thanks for the info.

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