Would love some advice/ help to fix our LX165 John Deere (has a Kawasaki engine- was bought used so we think its about a 1985-1990 in age). We bought the mower and it had a bad spindle. Our mower guy fixed the spindle for free since he was the one to suggest the mower for purchase from another customer. He tested the mower for just a short time on our even/smooth lawn and it worked fine. We took it up to our property that it was meant to be used at and began mower the more uneven land. Not 5-10 minutes later, the belt that runs from the tractor to power the deck (not the deck belt) was thrown off into the grass and the mower stopped working (duh!) 
After a few more times of this happening and us replacing it, we figured out the large spring that is attached to a 4-6" bar that pivots freely on the deck keeps losing tension because the bar spins around. With that bar pivoting, the spring comes undone and the tension on the belt is lost, throwing the belt.
We are tired of loading the tractor up, taking it to our guy and then waiting for it to be fixed. Is there anything we can do to fix it? Seems like it should have something to keep the bar in place because it moves pretty easily especially when hitting all the bumps we do while mowing. Does anyone have any pictures of what that piece and portion of the mower should look like to see if we are missing parts or have broken parts?
Thanks!
After a few more times of this happening and us replacing it, we figured out the large spring that is attached to a 4-6" bar that pivots freely on the deck keeps losing tension because the bar spins around. With that bar pivoting, the spring comes undone and the tension on the belt is lost, throwing the belt. We are tired of loading the tractor up, taking it to our guy and then waiting for it to be fixed. Is there anything we can do to fix it? Seems like it should have something to keep the bar in place because it moves pretty easily especially when hitting all the bumps we do while mowing. Does anyone have any pictures of what that piece and portion of the mower should look like to see if we are missing parts or have broken parts?
Thanks!