Ask the Mechanic

Steve Thompson, Contributor

READER: I have a 348 John Deere baler that has always had a vibration in it that I thought was excessive. It's like the whole baler had a shake to it. The vibration grew greater as the rpm increased. The dealer told me that I probably needed to change the bushing in the flywheel. I did, but it did not help. I noticed that the flywheel had some big places hollowed out. A guy at the dealership told me that these must be little places in the casting they took out. What could be my vibration problem? I know it's hard on my baler, and I'm afraid it will cause my sheet metal to crack.

STEVE: The flywheel on your baler is a heavy casting that spins very fast with a lot of energy behind it. That much weight spinning fast will certainly shake, rattle and roll a baler if the flywheel is not balanced or if the shaft is not spinning true and is wobbling.

In this case, I bet your problem is with the output shaft that comes from the gear case and through the flywheel. The flywheel is carefully balanced at the factory by drilling those round areas to create the balance, not remove defective material.

I think the output shaft is bent. This shaft is big, but if something were to hit the outside edge (like a truck backing into it), or if it was dropped at the dealership, it can bend. These balers are shipped with the flywheel facing down on a trailer, and if it were to fall off the truck or from the dealership's crane, the force would bend that shaft. A dial indicator placed between the baler and the flywheel while rotating the flywheel with the shear pin in place will show excessive movement of the flywheel.

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-- Email Steve Thompson care of askthemechaniccolumn@gmail.com, and be sure to include your contact information and phone number.

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