Hydraulic adjustments on 3 ton excavator ...

[V8Druid]

oops .... just seen the two posts before mine pop up .... we all seem to concur

 

[Wiggy]

Hi folks.
Thank you for your continued interest and input; it's VERY much appreciated.
I couldn't post this earlier as it was an XL sheet now saved as a .png.
Pics of valve block and other stuff coming soon.
Regards

 

[Wiggy]

That's not working very well so here's a pdf of the Chinese-English translations.

 

[wee_gus]

Yes looks high that servi pressure, out a gauge on it and check it, I would put it to 30 and see how you get on then

 

[wee_gus]

Also worth checking the nitrogen on that accumulator and make sure it ok, also check the bladder is not burst

 

[jd6820]

Also worth checking the nitrogen on that accumulator and make sure it ok, also check the bladder is not burst

Just what I was thinking, this could probably cause surges of pressure during operation as the pump is having to keep up the pressure as demand falls and rises. This would be jerky operation as opposed to smooth.

 

[V8Druid]

Yes looks high that servi pressure, out a gauge on it and check it, I would put it to 30 and see how you get on then

yeh 40 bar is a lot for a servo circuit, but that's what the RV is set at ?? ...... IIRC the 'Drema runs 34 bar and's smooth as silk. Can well imagine that extra 6 bar'd make the controls pretty twitchy .......
so too would a faulty accumulator with the inability to maintain a 'smooth' pressure from the servo pump, ironing out the 'spikes' as the demand varies with every movement of the sticks

@Wiggy ... the accumulator'll look summat like this

... has a bladder in it with nitrogen on one side (top, below) and oil the other (bottom)

the bladders can rupture, or the accumulator can lose pressure ... most are re-chargeable with nitrogen to the desired pressure - circa 40 bar in this case, according to your doc.s.
before tweaking the pressure down on the RV you will/would need to check what pressure the accumulator is/was filled to, or it won't have the desired effect of smoothing out any spikes, as it needs to be balanced with the desired circuit pressure

 

[Wiggy]

Good morning guys
Thank you everyone for your continued input.
Repaired dipper cylinder now back on and hydraulics exposed.
Please feast your eyes and let me know your thoughts.
Thanks in advance.

 

[Wiggy]

And a couple more ...

 

[Wiggy]

I'm getting behind with my thank yous but it's appreciated everyone.

 

[Wiggy]

For the hard of sight, these are the details on the various ID plates … thanks everyone.

Valve block ID plate says …

HUSCO-Kayaba
Hydraulics (Shanghai) Ltd
5000-G53
G06
K05 B238
Assembled in China -------------------------rolleyes

The main motor pump ID plate says …

KYB B0600 – 16021
PSVD2 – 17E – 12
S/N 550010
KAYABA INDUSTRY CO., LTD. JAPAN

Cummins Engine ID plate says …
04/12/05
700055371

 

[Wiggy]

yeh 40 bar is a lot for a servo circuit, but that's what the RV is set at ?? ...... IIRC the 'Drema runs 34 bar and's smooth as silk. Can well imagine that extra 6 bar'd make the controls pretty twitchy .......
so too would a faulty accumulator with the inability to maintain a 'smooth' pressure from the servo pump, ironing out the 'spikes' as the demand varies with every movement of the sticks

@Wiggy ... the accumulator'll look summat like this

View attachment 9214

... has a bladder in it with nitrogen on one side (top, below) and oil the other (bottom)

View attachment 9215

the bladders can rupture, or the accumulator can lose pressure ... most are re-chargeable with nitrogen to the desired pressure - circa 40 bar in this case, according to your doc.s.
before tweaking the pressure down on the RV you will/would need to check what pressure the accumulator is/was filled to, or it won't have the desired effect of smoothing out any spikes, as it needs to be balanced with the desired circuit pressure

Hi V8Druid. This 'faulty accumulator' sounds VERY promising.
I haven't had the time to explain some of the undesirable characteristics yet, but one is left stick cabin rotation. It's (almost) either on or off. Move the lever slowly and you get a little movement, a tiny bit more and you're into full movement with nothing in between!
Speak soon.

 

[V8Druid]

Hi V8Druid. This 'faulty accumulator' sounds VERY promising.
I haven't had the time to explain some of the undesirable characteristics yet, but one is left stick cabin rotation. It's (almost) either on or off. Move the lever slowly and you get a little movement, a tiny bit more and you're into full movement with nothing in between!
Speak soon.

have you checked out the buttons in the servo sticks for smoothness, as previously suggested ? No sticking or tightness ?

A shot accumulator would certainly give you harshness, but would expect smooth, gentle, progressive use of the sticks to give you at least some form of proportional control, rather than the on/off effect you describe

To have a suss of if your accumulator is possibly shot .... try .. raising the boom to get the bucket a foot or two off the deck. Turn the motor/engine off.... turn your ignition back on, but don't crank/start it ... and all with the dead man in working position, *(if you dead-man it, it will dump the pressure to tank)*
VERY gently try to lower the boom.
If the accumulator is ok it will provide sufficient pressure to the servo circuit to allow it to operate the main boom spool valve, to lower the boom ....if it doesn't move, there'll be no pressure left in the servo circuit accumulator, to op. the main spool.

 

[V8Druid]

Aiden @CPS ... or anyone, WTF is this?? .... top left of scematic

 

[CPS]

Aiden @CPS ... or anyone, WTF is this?? .... top left of scematic

View attachment 9233

Slew motor, with a diverter to the boom offset.

 

[V8Druid]

Slew motor, with a diverter to the boom offset.

cheers Boyo .... I could not see that for looking .... saw the diverter and cylinder and it just did not click

 

[Wiggy]

Good afternoon guys from sunny central France.
Thank you for your continued interest and input and I will get around to answering everyone's questions soon.
The people who fixed the dipper cylinder recommended a hydraulics chap who visited, but he didn't have the correct adaptor for his gauges etc! He had every other type in the world but not the one needed, which he's getting.
The machine is back in action but too bloody annoying for me to use.
I'm pretty sure I'm going to sell it and get something else.
Suggestions in the 2.5-2.8 ton range taking into account support. parts etc. would be appreciated.
A local guy hires out IMER excavators (made in Italy I think) and they seem great. I used the 2.7 ton one last week and it's controls are fantastic compared to mine!
When the hydraulics chap returns, we'll check the pressures and see if anything can be done.
I'll keep you posted.
Bon week-end à tous

 

[wee_gus]

Good afternoon guys from sunny central France.
Thank you for your continued interest and input and I will get around to answering everyone's questions soon.
The people who fixed the dipper cylinder recommended a hydraulics chap who visited, but he didn't have the correct adaptor for his gauges etc! He had every other type in the world but not the one needed, which he's getting.
The machine is back in action but too bloody annoying for me to use.
I'm pretty sure I'm going to sell it and get something else.
Suggestions in the 2.5-2.8 ton range taking into account support. parts etc. would be appreciated.
A local guy hires out IMER excavators (made in Italy I think) and they seem great. I used the 2.7 ton one last week and it's controls are fantastic compared to mine!
When the hydraulics chap returns, we'll check the pressures and see if anything can be done.
I'll keep you posted.
Bon week-end à tous

If your wanting a new digger, then I can highly recommend the Yanmar SV26, really really surprised me and it’s got bloody good power