Hitachi EX150LC Issues

[Dave Neubert]

If your swing box is empty you better pull it and tear it down the lower seal on the pinion is bad and maybe the bearing. It is possible that the swing motor or brake has pressurized the swing box and blew out the seal. although the box should have a breather I have seen people plug it thinking that they fixed the leak

 

[Bruce Hill]

Good day Bruce
Oil from the dip stick we assume is thin like hydraulic fluid if this is the case the swing motor is the culprit, if the shaft seal leaks it will drain into the the transmission (Should be gear oil) and the making passage into the swing ring bath. If this as we outline above leave the rotary shaft coupling, remove the swing motor renew the shaft seal - change the case drain filter as this could be the beginning of the seal failure. We suggest you pull the transmission and change the seal also.
If you can confirm that we have interpreted the situation correctly we will put some information,ation together for you.
Kind regards
Uffex

Good morning Uffex
When i first checked the transmissiion fluid levels the dipstick indicated empty. I added differential to full mark. A few days later, dipstick indicated empty again. If the case swing motor was the culprit, wouldn't there be hyd in the transmission ? I will pull the whole unit and inspect the shaft seal from the swing motor and the rotary shaft seal from the transmission.
Any information you may have to help with would be appreciated.

 

[Bruce Hill]

I would remove the whole assembly and replace seal on the bench. Because it’s really problematic to do it correctly and cleanly in place.

And I would look for reasons why seal failed, high case pressure caused by restriction in case drain hose or filter, wobbly shaft caused by failed bearing or bushings, or rough sealing surface of the shaft.


If you decide to do it in place at least pressure wash surroundings of work area really good, before starting disassembling anything, so when you will be working the dirt will not be falling in.

 

[Bruce Hill]

I will pull the whole unit, however I am interested in knowing that replacing this rotary shaft seal has been done in place ? I will be sure to investigate high case pressure caused by restriction in case drain hose or filter, wobbly shaft caused by failed bearing or bushings, or rough sealing surface of the shaft.
Thank you

 

[Dave Neubert]

I have always done the rotary seals in place age is what gets them they Deteriorate at 8000 hrs or so

 

[uffex]

Good day Bruce
We will make some information for you although we have the impression it is gear oil leaking into the slewing ring bath from what your last post said.
Kind regards
Uffex

 

[uffex]

Hi Bruce
Information may help.
Kind regards
Uffex

 

[Jakex120]

I'm curious. .does a leaking swing motor gear seal provide constant lubrication to the swing bearing assembly? ..

 

[uffex]

Good day Jakex
No that is not the common practice the motor is lubricated by the Hydraulic fluid - the transmission (gear) is lubricated by its own gear oil normally internal bath - the swing bearing is lubricated by greasing with a pump gun, there are some exceptions but this is the most common layout for the 360 degree excavator.
Kind regards
Uffex

 

[Bruce Hill]

Hi everyone. Wanted to touch bases with you all and tell you what I found. The rotary junction motor was definitely leaking all of the hydraulic oil that was found to be seeping from the turret ring. The lack of differential oil in the transmission was puzzling at first due to the recent teardown and rebuild from previous owner. It had been taken off the machine prior to my ownership and rebuilt with new bearing, seal etc. However, on putting it back together, they were a a little carless. Installing the large ring seal. It was bent in one place allowing differential oil to also leak into the ring turret. Bearings still looked brand new ..... yea ! Reinstallation starts tomorrow. Thank you for all your help.