ZT52HD DECK VIBRATION FIX

Adding a bit of weight in strategic locations often dampens harmonic vibrations. How much and where to put it is where the voodoo comes in.
 
mhavanti said:
Have any of you shortened the belt tension spring to see if that helps alleviate the belt flopping around. From the video, it appears to me the belt resonance is causing all of your metal parts to sing along with the belt tensioner moving back and forth in time. Maybe find a shorter spring before you cut and reshape yours.

Let us know if that brings a halt to the maddening Gravely Clamor.

Max
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This was one of my first thoughts as well after I pulled on that spring to cause more tension on the belt the noise went away. I don’t know where to get a hold of another spring to try out is the problem. Not to mention if more tension is put on the belt would it wear out the belt that much faster. The biggest help for me has been keeping that bar pushed in. I stuck a rubber riser that had peal off adhesive on the bracket so that the bar cant migrate out nearly as much. I’d say the noise is around 80% better with this fix. It was also a bit better after my dealer tightened every bolt around the deck.
 
You could try something like a trampoline spring ( cause they are easy to get ) pulling against the tension spring to damp out the vibrations .
Other than that cut some washers out of a milk bottle ( if they are plastic ) and use them under the tension arm pivot to load it up a little and slow down the movements.
 
If there are any open areas on idler pulley arms, attach the heaviest magnetic weights that will fit. If this helps, attach the weights permanently.
 
My dealer has had my mower for just over a week now. He believes he knows how to resolve the problem and is waiting to hear from Gravely. He said the bracket that holds the metal pin that moves in and out is out of alignment just enough to allow the floating and then the vibrations. It stops when you push on it because by doing that you are putting tension on it as there would be if the bracket were aligned correctly. The bracket is welded onto the frame so the two options are either a new deck shell or he bends the bracket slightly to put the correct tension on the pin. I would prefer to have a deck shell that is correct from the factory so we will see what Gravely says. Dealer has been great to work with and has really taken the time to find the problem and address it. Now up to Gravely to do the same.
 
Glad to hear your dealer is doing what he claimed he'd do when he sold you on his service. As it should be.

Hope they resolved the problem permanently for you.

Max
 
Quick update, Gravely has replaced my deck shell under warranty as they believe the misaligned bracket is causeing there not to be tension on the metal pin and allowing it to move which then causes the noise. Seeing that it could take a few weeks to get the new deck shell the dealer has given me a ProTurn 260 to use in the meantime. The 260 is an absolute beast of a machine and I may not be able to go back to the HD52! The one interesting thing though is that I think my HD52 actually cuts better than the 260. The 260 cuts fine but has a tendency to leave uncut blades of grass here and there where I don’t notice that on my HD52. Not a big deal and wouldn’t stop me from using it but just something I noticed.
 
I got to play with my friend's ZT52 today. I think we reduced, but didn't eliminate the vibration. We ran out of magnets before we ran out of vibration.

I noticed there is a huge amount of deflection going on with the main drive belt. The belt looks good (mower has 50 hours on it) but I can't imagine it lasting very long whipping around like that.

The belt that runs the RH spindle is a segmented belt. I wonder why? But there wasn't nearly the belt deflection or idler movement on this belt. The belt that powers the center and LH spindles is the one that is thrashing around the most.
 
*Update* my deck is fixed! No more rattling noise. The only noises I have now are just the sounds of the blades and belts which are normal. The dealer swapped the original deck shell with a brand new shell and it totally solved the problem. They said there was a bracket on the original deck that was misaligned which was allowing one of the hangers for the deck to move and then cause the rattle. I made a video of that piece moving. With the new deck shell that hanger doesn’t move anymore and there is no more rattling.

If you’re having this problem tell Gravely that you want your dealer to replace your deck shell with a new one from the factory!
 
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