Volvo EC15B swinging problem by arm move down

[wowe]

Muz, I believe that hydraulic oil is the best for hydraulic. But nevertheless I believe, that for a short check the 6L 15W40 are usable. I have ordered 33L hydraulic oil for a complete Change of the oil after the test. I just went to the digger and tock a sample of the oil. About 1.5 h after the last run there were absolutely no bubbles. Now itīs too lat for starting the motor. Tomorrow I will make a short test to see if there are bubbles in the oil immediately after running.

[ianoz]

Watched the Video again .Hard to tell on such a short video clip .
Could be as simple as TOTAL Inexperieanced operator .
Watch the lever . To be smooth in operation lever movements need to be the same .Jerky lever movements equal jerky arm movements .Pilot control levers are VERY sensitive

[Muz]

Muz, I believe that hydraulic oil is the best for hydraulic. But nevertheless I believe, that for a short check the 6L 15W40 are usable.

Ok .. have a go then .. let us know how it goes ?

bout 1.5 h after the last run there were absolutely no bubbles.

was that before you put the engine oil in or after ?

[wowe]

So, today I made a 1-2 hour digging. I tried to realise a very sensitive steering at boom down. At the down movement I felt that the boom was Swinging at the same frequency as at my first Video, but the amplidude was small. I made no medium speed down movement, because this is the range where the swinging amplitude is rather big.

I made a new video:

Muz - to the bubbles. I took a probe immediately after diggering. Here is the picture:


Blasen im Hydrauliköl.jpg

I estimate that the distance between the small bubbles is about 2-3 mm or 1/10 Inch. So there are bubbles, but I donīt know the consequence of them. So it is a riddle, if These bubbles can cause the whipping with no load (the bucket at the first Trial with heavy jerking was empty).


So I come back to the old question how will we continue the procedure? As an inexperienced digger mechanic - but I had become a car mechanic many years ago - sugggested 2 things:

1. I will remove all filters and meshes in the hydraulic circle and clean those which are cleanable.


2. I will change the hydraulic hose at the Joystick so up and down is changed. So I can see, if the behaviour has also changed and the jerking is at up.

3. Maybe I will try to reverse the buying. But the digger seem really in a good condition - except the jerky boom down movement. At least I can produce jerking - maybe I can permit it a Little bit.

Thanks for reply.

[Muz]

Everything in your video looked fine ? .. sounds like you are operating it at half revs ?

[wowe]

Everything in your video looked fine ? .. sounds like you are operating it at half revs ?

Yes - I think I need not more power to do this job. Or must the power always be at maximum?

[ianoz]

The more revs , the more oil flow the smoother the operation with EXPERIENCE .
With MY experience I believe , the smaller the machine ,the harder it is to make it work smoothly .
I believe to operate a machine there must be at least two movements happening at the same time.
All of that being said with the lever movements , is there any difference in feel ?
And also please explain what you mean by "Swing "
Swing to me is movement left and right ,
I myself if I was in your shoes , would see if i could find n experienced operator of small machines , and ask him to operate it and give his opinion .
An experienced man sitting in the seat will know straight away if it is a machine fault . Where us sitting here watching a video can't feel what it is doing , and can only guess .

[wowe]

And also please explain what you mean by "Swing "
Swing to me is movement left and right ,

You are right.

I myself if I was in your shoes , would see if i could find n experienced operator of small machines , and ask him to operate it and give his opinion .
An experienced man sitting in the seat will know straight away if it is a machine fault .

Yes - I think the same. Last week as I got the digger, I asked a experienced worker at a digger, if he can Show me, how to use it. He worked in my Volvo about 3 Minutes and said, that this machine is a good one. But this was before I realized this jerky problem. I will try to ask him next week for a new trial.

[ianoz]

You are right.



Yes - I think the same. Last week as I got the digger, I asked a experienced worker at a digger, if he can Show me, how to use it. He worked in my Volvo about 3 Minutes and said, that this machine is a good one. But this was before I realized this jerky problem. I will try to ask him next week for a new trial.

.
Well his responce tells me the machine is OK , It is the operator that needs work .
We were all learners at some stage .
I suggest , you ask him to show you the basics , Then you practise .
Once you feel you have control of the machine .Then ask him to come and watch you operate .He should then be able to offer advise after watching you on how to fine tune your operating skills .

[wowe]

And also please explain what you mean by "Swing "
Swing to me is movement left and right ,

Only to be correct: swing means a periodically movement: left and right, up and down, forward and back and so on. In my case the whole cabin of the digger swings forward and back.

Well his responce tells me the machine is OK , It is the operator that needs work .

At least itīs not so that the machine is absolutely waste. But the specific working situation was this, that the operator worked 95% with the shaft and only about 5% with the boom. So the problem canīt be obvious.



@Muz: Can you say something about the bubbles? Are this too much? must there be Zero bubbles for a perfect operating? I googled. What I red was, that the air in the oil which is solved in it doesnīt disturb the hydraulic. But if there are bubbles this is a Problem. And in my probe are bubbles. The question is, are this too much? Maybe it canīt be answered sure.

[Muz]

@Muz: Can you say something about the bubbles? Are this too much? must there be Zero bubbles for a perfect operating? I googled. What I red was, that the air in the oil which is solved in it doesnīt disturb the hydraulic. But if there are bubbles this is a Problem. And in my probe are bubbles. The question is, are this too much? Maybe it canīt be answered sure.

No, I have to say that sample looks ok to me.

In answer to one of your other points, you should have the revs at maximum, for 'most' digging operations

[wowe]

To the oil: now - over 12 h after the last working - I took a new probe: The bubbles have gone.

In answer to one of your other points, you should have the revs at maximum, for 'most' digging Operation

Thats hard for me. I prefer to make a save usage of the things I use. Iīm suffering with the material. But I will remember to the advise next time.

wowe

[wowe]

Muz, you said that the oil seems ok. But there are these little bubbles with an distance of about 2mm to the next one. Is this acceptable? The bubbles are more visible, if you expand the Picture.

Question: Could be air in the cylindre of the boom? I think - but Iīm no expert - that the oil in the cylindre is not in a loop and doesnīt circulate. So if there is air in the down cylindre, it would be there all time. Is this right? And how must the boom-cylindre be bleeded?

regards wowe

[Muz]

You need a fair bit of air mixed in the oil for it to have an effect. Theres no doubt, putting engine oil in there is not good, but the sample you showed didnt look 'too' bad to me, perhaps because modern engine oils have a wider viscosity profile .. I dont know ? Even hydraulic oil does get some air in it, but from what I can see from your pic, I dont think thats your problem

[ianoz]

Watch your video for clues .
The machine is not sitting on level ground ,so it is rocking back and forward
To counteract this the blade can be placed on the ground.
A small excavator like this is very unstable , It is the nature of the beast .
Add to this a very inexperienced operator that will not open the throttle to let the machine work as it is intended , It all adds up to a very harsh action .
A good operator makes it look so easy , so you think it is easy .
So when the machine jumps and bucks . Must be the machines fault Well no it is not .
I can't guarantee hours in the seat will make you a good operator .But if you listen to good advice It will get you a lot closer .