Impact wrench blade removal

Discussion in 'eXmark' started by troberts, Jan 8, 2003.

  1. troberts

    troberts LawnSite Member
    from Indiana
    Posts: 45


    I have an eXmark Metro 48, fixed deck, gear drive, walk behind (year 2000). I'm wanting to use an impact wrench to remove the blades, and have a couple of questions:

    1. Is it o.k. to do this (will it harm anything - like the spindle...)

    2. What is the best technigue for removing them with the impact wrench (provided that it's acceptable to use one) (i.e. Should I just put the wrench on the top bolt and go for it?

    3. Can I use the wrench to tighten the blade once I put them back on?

    Thanks again for the help,

  2. eXmark

    eXmark Manufacturer / Sponsor
    Posts: 4,258


    Good question, here is how I would do it. First of all it would be hard to cause damage to the spindle with an impact. Although anything is possible. You would have to rattle hard and long with a big impact.

    The most efficient use of the impact would be using it on the nut instead of the bolt. Turning the long bolt though the spindle will take more torque than turning the nut. That being said I would put the impact on top and a wrench or breaker-bar on the bottom.

    Here is what you want to watch for. Having the bolt too loose is probably a bigger issue. Usually the problem is the bolt is really tight when it is time to change the blade. We would like you have the bolt torque 75ft.lbs or greater and not to go above 100ft.lbs.

    3/8 impact would be about right for what you need but 1/2 can be use as long as you don't get too aggressive. It is always good to check your torque. If you are using wrenches you should crank'em down good and hard.

    Thanks Fred.
  3. chariot

    chariot LawnSite Senior Member
    Posts: 319

    I would like to ask this question about a 2002 EPS Z. Will I damage anything if I use an impact wrench to remove and re-install blades on this mower? I would be removing it by using the bolt from the bottom. I know that is specifies a recommended way in the manual, just wondering what would be at risk. This is the method that I have used on all of my other mowers, yours is the only one that I can remember saying to hold certain torque on the nut. Thanks
  4. eXmark

    eXmark Manufacturer / Sponsor
    Posts: 4,258


    First and explanation regarding the torque spec. on the blade bolt. The reason we recommend that you torque the blade to 115-120 ft. lbs. is to ensure that it is tight. If the blade bolt is not tight and you hit something or get into some tall wet grass that creates excessive drag on the blade it can self tighten and become extremely difficult to remove. A tight bolt is less likely to allow the blade to spin and thus less likely to allow the bolt to self tighten.

    An impact should not hurt anything. We use one to install the blades in assembly and that's all we use on our test machines as well. There has been some speculation that excessive use of an impact wrench to loosen over tightened bolts can allow the top nut to back off slightly. This would cause a loss of clamp load on the spindle bearings however we have not been able to produce such a result. Just to be safe simply double-check the torque of the top nut a couple of times per year and you should be in good shape.


  5. chariot

    chariot LawnSite Senior Member
    Posts: 319

    Thanks, that is good to know. This will save me some time, and money.

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