Hi all, I just acquired an EX150LC Hitachi, and I'm losing substantial amounts of hydraulic oil through the swing motor (bleeding through to the turn table ring gear). I will be pulling the swing motor tomorrow, figuring it is a seal of some sort. There is no differential oil showing on the dipstick, but it is definitely hydraulic oil that I am losing. Advice, please. -Bruce
One advise - make sure you loosing oil through the motor and not through hose fittings or even center pivot/rotary manifold. Might just save you money!
Good day Bruce There are a couple of possibility's one you may have overlooked is the central passage, some machine can leak hydraulic fluid into the turn table chamber, its strange you have no hydraulic fluid in the swing transmission, I attach a picture of the 120 but I believe it is similar. Kind regards Uffex
It is dry above and around swing motor. Central passage ? Center pivot/rotary manifold ? Would you please explain ? Thank you for your input !
This central passage you are referring to, is the same as the Center pivot/rotary manifold ? Where is this located ? Is this part of the swing motor ? What lays just ahead ( toward the front) of the swing motor. It has a couple of Hyd lines to it. The swing motor appears to have been replaced or rebuilt at some point. Newer unpainted bottom half. This type of issue is a first for me. So is the Hitachi.
Where is the center pivot rotary manifold you are referring to?
That’s the thing right smack in the middle of turret, the Oil passage to motors, swing motor usually in front of it. Yes you have hoses going to it on top and from it to motors underneath.
Good day Bruce The central passage is right in the centre of the machine, if you follow the hose or tubes from the valve chest you will find a bunch of four arrive at the very centre of the machine, this also is known as rotary coupling - rotary manifold . We will try and find a map if you need. Kind regards Uffex
Good day Explanation
Is it most likely that my hyd oil is coming from the rotary manifold ? Is there a method of determining what I should tackle first. I am leaning toward the removal of the rotary manifold first. Leaking this much hyd oil should be pretty obvious ?
Good day Bruce Its a dirty job but crawl beneath the machine look up at the underside of the centre passage if you can see fluid this is where you need to be. KR Uffex
Good day an actual illustration we found maybe it helps. KR Uffex
We were underneath and yes all your input has been very useful. The unit has been sitting idol for several days. When looked at more closely, we found hydraulic oil dripping from the turret ring gear. I belieive it was said earlier that it is likely this has accumulated most likely from the area around the rotary manifold ? We are going to remove the rotary manifold and have a look. Wish me luck. If you think of anything more, I am all ears .
Are you refering loosing oil through the swing motor ? Is this common ? Is it more heard of that the center pivot rotary manifold needs to be rebuilt ?
Dear Sir I had mentioned earlier in this thread that there was little to no differential oil in the swing motor. I would like to know if this possibly is an indication how hydraulic oil might be finding it's way to the turrett pan causing me to loose substantial hyd oil. Most of our focus has been on the center joint of which we had pulled last night. We plan on tear down and new seals etc., however having found not oil in the swing has given me questions. I put differential oil in to see if it would maintain proper level while rebuilding the center joint manifold. Would this give me any indication whether or not I should pull this as well ??
Good day Bruce We are a little confused by your terminology so we will try to clarify, the motor transmission illustration above item No.10 is the motor this is driven and lubricated by hydraulic fluid, for the fluid to make passage to the swing ring it has to fill the transmission that is below item No.10. The transmission should have light gear oil to lubricate the planetary gears. If the gear oil is present at at the correct level the issue is not from these components.We cannot find any other possibility for hydraulic fluid to enter the swing ring. I should add fluid will normally flow from the dip stick when the motor shaft seal leaks. Kind regards Uffex
Good day Bruce A contact sent an extract sorry the quality is not so good but it may help. Kind regards Uffex
I am loosing oil from the dipstick. What kind of job is required then to repair the motor shaft seal ? I have pulled the center joint rotary manifold and am awaiting seal kit. It is assumed then that this issue is a combination of loosing differential oil through the rotary shaft seal (not hydraulic from drive above) and the rotary manifold (hydraulic) center joint, into the swing ring. Is this correct in your opinion ? Sincerely Bruce
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
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.
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
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.
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
I have always done the rotary seals in place age is what gets them they Deteriorate at 8000 hrs or so
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
Hi Bruce Information may help. Kind regards Uffex
I'm curious. .does a leaking swing motor gear seal provide constant lubrication to the swing bearing assembly? ..
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
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.