hi all. My hitachi ex60-3 was recently leaking oil out between the final drive and sprocket. I replaced the brake piston seals, which were shot, drained the final drive and refilled to the correct level with gear oil. Even though I didn’t replace the duo cone seals on the final drive, I said would it stop leaking if the brake piston seals fixed the problem. That was a few months ago, and I had no leak out of the duo cone seals up until yesterday. Haven’t ran the machine much over the winter but have started to use it the odd day now again. Yesterday when I finished a job I noticed that the same leak had started again. Final drive was again filling up with hydraulic oil. So I took off the hydraulic motor and removed the brake piston, but the piston seals were still perfect. I then looked at the motor and saw that the output shaft seal was the source of the leak, so I disassembled the motor and replaced the seals in that. All back together today and tracking away fine, tracking straight and loads of power. Question is would you think it is excessive pressure, i.e. case drain, or just normal wear and tear in the seals, that caused the leak? Machine has approximately 5000 hours, if you could believe the clock. Just wondering should I do the swivel seals or is there any check to see is the swivel joint bypassing from the high pressure side to the case drain side? Or if anyone has any other ideas, I’m all ears. Thanks
Good day Case drain is always suspect in such leaks, I suggest you change the case drain filter and check the pressure as you work the machine. Kind regards Uffex
Thanks for the reply. Machine doesn’t have a case drain filter, one large return filter in the tank, one screen filter at the bottom of the tank for pump intake and pilot control filter.
Good day The pressure should not exceed 1.5 bars over pressure can be as a consequence of a worn component unrelated to the track drive. Kind regards uffex