Backhoe 2010 John Deere 485 Backhoe Dipperstick actuator issues

[Beechboy]

Good evening folks.
I have an issue with my dipperstick Actuator. The other day I was digging when the dipperstick failed to respond to inputs. I removed the actuator from the tractor and tore it down. What I found was the actuator piston rod nut laying in the bottom of the cylinder along with all the threads from the piston. Any idea what would cause this other than bad heat treating, and has anyone else had this issue or know of any recalls.

Thanks for any Input
Regards
Curtis

[dfkrug]

Wow, I have never seen that.

My guess is the piston nut got over-torqued at the factory, and/or the nut was
oversized. Or threads on the rod were undersized. Or a crappy batch of nuts
or rods.

It often takes me a good 300-400 ft-lbs of torque to remove piston nuts.

I have seen 2 cyls with loose nuts, but good threads.

[uniqman]

hello,
another possibility is that nut went loose because of vibration. That's quite common on backhoes or poclain type machinery that yse hydraulic braker for a long time.