Bent shaft on Snapper 21" commercial mower

Discussion in 'Mechanic and Repair' started by Blade-o-grass, Apr 5, 2006.

  1. Blade-o-grass

    Blade-o-grass LawnSite Member
    Messages: 47

    I was mowing yesterday and hit a piece of pipe that was sticking up out of the groung that I didn't see until it was too late....the shaft was bent making the blade about 1" higher on one side...I made sure to check the blade and see if the blade was bent and it is still strait....
    There is a rubbing/scraping noise from within the mower and there is a major vibration going on...
    My question is, Is the shaft something that I can replace, or would I need to put a new engine on......This mower is only 4 months old, but the warranty does't cover this.....
    thanks for helping
  2. lawnspecialties

    lawnspecialties LawnSite Silver Member
    Messages: 2,524

    I had the same thing happen to my Deere with a Briggs & Stratton two years ago. It was only a couple months old and the Deere dealership told me I'd just as well replace the $400 mower! A local mower repair shop had a device for fixing this very problem. He pulled the engine, straightened the shaft, and it was less than $50.:) Never gave me a problem since.

    Call around to some small independent shops and see if they can do the same. Good Luck
  3. J&R Landscaping

    J&R Landscaping LawnSite Fanatic
    Messages: 5,095

    Some shops will straighten the crank, others will replace it. Sometimes, just straigthneing the crankshaft will cause you to blow oil seals and flywheel keys left and right. For this reason, my dealer only replaces the shaft. He doesn't straighten them.
  4. Lawn Masters

    Lawn Masters LawnSite Senior Member
    Messages: 850

    I'd replace the shaft. to be smooth and not vibrate or cause mechanical problems later, the shaft must be straightened to precise tolerances, putting a new shaft in is just as simple, and less risk.
  5. Restrorob

    Restrorob LawnSite Fanatic
    Messages: 11,029

    Once a crankshaft is bent it changes the molecular structure of the steel and weakens it, Another hit could send the crank end and blade flying out and hurt somebody. For this reason we only replace them instead of straightening.
  6. newz7151

    newz7151 LawnSite Silver Member
    from Tejas
    Messages: 2,419

    And hopefully, you have not run enough yet to waddle out the seal.
  7. ed2hess

    ed2hess LawnSite Fanatic
    Messages: 14,556

    Most shops have a press but they don't want to be responsible for any you gotta take a lot of beer and stuff to get it done unofficially. Simply way to expensive to replace a crank...I believe.
  8. oldrustycars

    oldrustycars LawnSite Senior Member
    Messages: 301

    ive straightened a few cranks, with SOME success. but theres a big chance for failure, so just do the job once, and get a new crank. replace the flywheel key too.
  9. lawnspecialties

    lawnspecialties LawnSite Silver Member
    Messages: 2,524

    I agree with everyone here but concerned over the costs. That $50 sure was nice compared to breaking the motor down. If it was a 25hp Kawasaki or something, sure, replace the shaft. But we're talking a small (less expensive) engine. I never had a problem with mine ever again.
  10. Dweezil

    Dweezil LawnSite Member
    Messages: 66

    Anytime Ive had someone ask about straighting, I tell them it's $50 up front and I'm not responsible if the crank snaps in the process or if the seal is blown. I also give them a quote for a new crank+ labor and let them decide what they want to do.

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