Make sure to raise excavator arm all the way up before servicing hydraulic cylinders. Standard operating procedure.I made hydraulic cylinder end caps for Eaton. Part of the training process was a day on the test bed. Even the smaller cylinders were not to be messed with. They could blow a hole thru a person and not even slow down.Seems like none of these people have seen the greatest safety film ever made: Shake Hands with Danger