1. Missed the live Ask the Expert event?
    Catch up on the conversation about fertilization strategies for success with the experts at Koch Turf & Ornamental in the Fertilizer Application forum.

    Dismiss Notice

stripped threads

Discussion in 'Mechanic and Repair' started by Grass Cake, Oct 16, 2006.

  1. Grass Cake

    Grass Cake LawnSite Senior Member
    from Zone C
    Messages: 303

    Kubota ZD18
    2yrs old...app 400 hrs

    Earlier in the year i hit a stump in some overgrown grass, at the time i thought things were Ok...but later that week when removing the bolt
    that holds the blade, it stripped the threads while removing it( slightly bent). I purchased a threader and new bolt and all was well....
    NOT!...after removing them several times the threads are now sloppy.

    I've noticed the other spindle threads have gotten a little slop also after repeated impact wrench changes. All spindles are fine otherwise.

    Spindles are 90.00 a piece....Do I

    a. suck it up and replace them all
    b. buy a high quality helicoil kit
    c. trade it for a new anvil?
  2. grass_cuttin_fool

    grass_cuttin_fool LawnSite Gold Member
    Messages: 3,526

    Ive had great succes with heli-coils over the years. Not sure int his application though

  3. Jim@MilkyWay

    Jim@MilkyWay LawnSite Senior Member
    Messages: 472

    Or, there is option:

    D. Do not tighten to 'point of no return' using impact tool. Use a torque wrench and tighten to oh, idunno, 30ft lbs. give or take 5. At least for a few times to "get the feel" of how tight to get them by hand with no aid required.
  4. Grass Cake

    Grass Cake LawnSite Senior Member
    from Zone C
    Messages: 303

    sounds hunky dory....but a torque wrench doesn't help my present situation. I'm sure the stump caused it though.
    smirk......what can i say...i like power tools
  5. Mickhippy

    Mickhippy LawnSite Platinum Member
    Messages: 4,274

    Replace them!
  6. Jim@MilkyWay

    Jim@MilkyWay LawnSite Senior Member
    Messages: 472

    Me too!
    Sorry you have the likelihood of replacing the spindles.
    I think they are made of pretty good steel, so what does it whisper to you if one is stripped and the other one feels sloppy? Furthermore, you probably have 1inch MIN of thread in there. That's tough to f**k up, but it can be done.
    Use Permatex, gray anti-seize lube, as has been suggested, on _everything_ that is critical, especially if it gets a lot of R&R
  7. Grass Cake

    Grass Cake LawnSite Senior Member
    from Zone C
    Messages: 303

    it has been observed that in a normal thread assembly a bolt is subjected to an average tightening load of more than 70% over first two threads near to its collar or over a few threads finding a proper surface contact.

    even at 4-5 threads ...the thread size of those 12mm bolts are lame!
  8. olyman

    olyman LawnSite Gold Member
    Messages: 3,649

    helicoil it--the helicoils are made of spring steel--can you say tough--and when you put them in--coat with a bit of blue loctite--ins---theyll hold--just stop using the impact--torque wrench as one suggested--i just use a ratchet and socket--and do it by feel-and have for years--never had one come loose--but have bought used mowers--oh my--impact out!!!!
  9. fixer67

    fixer67 LawnSite Silver Member
    Messages: 2,098

    I do not know about your ZD18, have not worked on one yet. But on some machines you can replace just the shaft and not the whole thing. Check your parts manual and see if you can do this with your unit.

Share This Page