152z squealing with blades engaged

Discussion in 'Mechanic and Repair' started by copotay, Oct 20, 2009.

  1. copotay

    copotay LawnSite Member
    Messages: 65

    420 hours, replaced belts about 6 months ago, and everytime I engage the Pto I am hearing a whining/squealing noise which sounds like it is coming from beneath my feet around the center spindle. This has been going on for about the last 40 hours of operation and cannot figure it out. It seems to squeal a little louder when going into heavy grass and never really stops until I disengage the PTO. I have had replaced all the idler pulleys to no success. I checked the spindles for free movement spinning them without the belt on and the only thing I found was that the center spindle has what sounds like a short slight rub once every full revolution, so before I go and spend money to replace the spindle I was wondering if it could be anything else? I also researched the entire website for the last two hours reading posts but could only find something about the belts possibly making noise and someone suggesting spraying WD40 on the belts, but I would think that would call slippage if nothing else. Any help greatly appreciated.
  2. waters lawn care

    waters lawn care LawnSite Member
    from alabama
    Messages: 128

    I have same mower with 650hrs never that problem.In saying that i have a jd tractor type mower that would do the oppisite on squealing when blades were disengaged had to replace eletric pto clutch.Problem solved post back if you find problem so i can be on look out for other problems
  3. copotay

    copotay LawnSite Member
    Messages: 65

    Ok, no problem I will, it doesnt squeal when it shuts down it just becomes a whole lot quieter.
  4. txgrassguy

    txgrassguy LawnSite Gold Member
    Messages: 3,083

    Check the idler arm bushing - it is a cheap insert on the shaft that the idler arm pulley moves back and forth on.
    Also, once the deck is engaged prop the deck plate open and spray wd-40 directly on to the top of the pulleys one at a time in an effort to isolate an early bearing failure.
    If this doesn't stop the squealing spray the deck belt with belt dressing.
    Before anything else though check the belt for signs of uneven wear, same with the pulleys - there will be signs of the uneven wear but use a good flash light or drop light - just don't rely on ambient light for uneven wear marks to appear.
  5. Restrorob

    Restrorob LawnSite Fanatic
    Messages: 11,029

    Did you install factory replacement belts ?

    Spraying anything on the belt will not solve the problem, I had the same problem with a customer's Zoom (twin to your 150). Can you post the full model AND serial numbers off your unit ?
  6. copotay

    copotay LawnSite Member
    Messages: 65

    Tks Txgrassguy I will check everything as you advise on Saturday my next day off and post the results.

    Restrorob: OEM from the gravely dealer and the model is 992044 ser 2600
  7. copotay

    copotay LawnSite Member
    Messages: 65

    Txgrassguy, looking at the deck you are speaking of 12,13, and 32 on the other arm, I did not think of those especially when hitting heavy grass making those spring loaded arms move alot.

    ScreenHunter_06 Oct. 21 07.50.jpg
  8. Restrorob

    Restrorob LawnSite Fanatic
    Messages: 11,029

    Here's a post I made on another board about belt slippage on the Zoom, There are only slight differences between it and the Gravely.


    I see your Gravely has a bolt on bracket the idler arm spring mounts to, The before pic below shows how this bracket should be mounted now.

    By turning this bracket around and mounting just like the after pic will give you more tension on this belt and should eliminate the slipping problems, That is if the belt hasn't been ruined/stretched too badly from running it 40 hours slipping.


    BTW, I done this modification 8 months ago and the customer has brought other equipment in since and tells me it's still mowing just fine.
  9. copotay

    copotay LawnSite Member
    Messages: 65

    Tks Restrorob great suggestion, I will definitely check this out, I have ran with the same new OEM belt for near 100 hours until it started doing this about 40 hours ago. I dont know if this makes a difference but when I took the belts back off again to check the spindles I really had to use some force to undo them and put them back on because the springs were so stretched and tight, it seems the belt was also tight IMO. When I get into tall or thick grass I am not getting any skipping or anything and the engine does bind down when in this type grass. This weekend I will have time to try everything ya'll are suggesting and I hope I can figure it out. Glad to have your help
  10. Restrorob

    Restrorob LawnSite Fanatic
    Messages: 11,029

    All spring tensioned belts are hard and require a lot of force to remove/install unless done as below.

    From another of my post;


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