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Toro 580D Groundsmaster Excessive Belt Wear

Discussion in 'Lawn Mowing' started by Airport Crew, Jun 28, 2005.

  1. Airport Crew

    Airport Crew LawnSite Member
    Messages: 2

    We have been using a 1993 Toro Groundsmaster for the last few months to mow our runway and infield. The area is about 10 acres, all combined, and is mowed once a week. The main drive belt of the center (front) deck has been wearing at an alarming rate. We had to replace the belt after only 18 hours of use. At $100 a pop this seems a bit excessive. The outboard belts are doing fine, as well as the belts on the two wing decks. After inspecting the the main belt drive-train, all idlers and pulleys are free to rotate and are properly aligned. The new belt was installed and tensioned according to the manual. This is a double-vee belt (six sided) and should wear much longer. There had been a sign that all was not well, as there was a constant black rubber dust below the belt. We were unable to detect the origin of the wear. Has anyone had a similar experience with this machine? Any ideas on what could be wrong? This belt is tensioned by a loading spring (not measured by belt deflection at a center point).

  2. cushman

    cushman LawnSite Member
    from se pa
    Messages: 36

    I'd look for rust in the pulley grooves. I once bought a mower that was sitting outside for awhile and it wore out a deck belt in a few hours.

    After finding the rust, I ran the mower while moving a file around the inside of the pulleys. (carefully, of course). The pulleys were then pitted, but shiney.

    That was in 1989 and the machine still has the same belt. 100's of hour since.
  3. Airport Crew

    Airport Crew LawnSite Member
    Messages: 2

    Thanks for the tip. I will look into the rust issue tomorrow. This machine did spend some time out in the weather last winter. It could well be the problem.

    Thanks again!
  4. LawnCrafters

    LawnCrafters LawnSite Member
    Messages: 133

    We,ve had the very same problem with our 580-D. If there are alot of hours on the machine the pulleys actually wear out. The belt eventually wears the groove of the pulley wider and the belt sits deeper in the groove. We were burning up a hex belt every few days! Since I replaced the drive motor pulley and 3 or 4 of the spindle pulleys I haven't had a problem yet.
    To tell if they're worn out just run your finger in and out of the groove and feel if it's nice and flat or if there's a ridge. The pulleys, drive or spindle, are about $50 a piece.
    I hope that makes sense. Let me know if you have any other questions. I've pretty much replaced the entire cutting system on one of these machines.
  5. Yep, I'm betting LawnCrafters has the answer. My center belt lasts 1,000 hrs or so.

    Something else you may check though are the REAR castors on the front deck. They catch everything from the front deck and the bearings go out without being very noticable. This lets the rear of the deck drop putting a lot of extra load on the center deck. How's your quality of cut? Does the grass from the center deck look "stirred" from the back of the blades passing thru it a second time?

    It's a remote posibility. I'd still bet on the drive pulley being worn out.


    OH! BTW It's sooo easy to replace this pulley. Just unbolt the plate it's mounted to. Flip it over. Take out the two set screws with an allen wrench. (WD-40 helps)
    Then just insert a 1/4" bolt in the OTHER threaded hole and the pulley pops right off.
    You may have seen one of these before, but the first one I ever saw I destroyed with a pulley puller.

    Good luck.

  6. LawnCrafters

    LawnCrafters LawnSite Member
    Messages: 133

    Those pulleys are called taper-lock. Sometimes they're on there so tight that the bolt will just strip the threads when trying to get the center hub out. If that's the case just smack the pulley in towards the drive motor with a hammer (or air hammer). It will pop right off. Then just push a flat screwdriver into the slot on the tapered hub to spread it out a little and it will slide right off.

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