Doosan dx140 hydraulic issues

[Richard Hunton]

Having an on going issue with the lift rams on my dx140.
I've had it from new , it's just clicked over 1000 easy hours.
The bounce in the rams is becoming impossible. Can not grade with it.

The check valves have been checked and bleed.

Air in the rams was another suggestion, these have been bottomed out and itsade no difference.

Anyone ever come across anything like this.

All help greatly appreciated, I'm also looking for a hydraulic schematic diagram if anyone can point me in the right direct.

Rich

 

[wee_gus]

What year of machine?

 

[hiluxman]

Have you tried bypassing the check valves?

Im not mega clued up on this but ive had ith where check valves have been the issue

 

[Richard Hunton]

Anyone know how to get round this. I can't get the video to upload

 

[Richard Hunton]

What year of machine?

New in September 2017

Dx140lcr 5

 

[doobin]

You'll need to post a video to YouTube then embed it on here.

 

[Richard Hunton]

You'll need to post a video to YouTube then embed it on here.

That sounds farrrrrrr toooooo technical for a digger driver like me lol.

I'll have a go tho

 

[Andy Gaffer]

Hi Richard, I mentioned in my other posts that I had issues with mine but these were due to the pilot pressures being increased by trying to solve the poor tracking which in turn made the ability to grade with it harder, I didn't get a bounce but more of the stick being too responsive when using it a speed, ok when it was slow but you had to keep the bottom of the bucket on the ground to stop it, mine was a dash 3, the dash 5s I had a go one felt a lot more refined than mine and looking back I may be should of purchased one them, you live and learn.
Id assume it must be out of warranty by now?

 

[wee_gus]

I’m going to have a stab and say a pilot issue.

 

[Richard Hunton]

Hi Richard, I mentioned in my other posts that I had issues with mine but these were due to the pilot pressures being increased by trying to solve the poor tracking which in turn made the ability to grade with it harder, I didn't get a bounce but more of the stick being too responsive when using it a speed, ok when it was slow but you had to keep the bottom of the bucket on the ground to stop it, mine was a dash 3, the dash 5s I had a go one felt a lot more refined than mine and looking back I may be should of purchased one them, you live and learn.
Id assume it must be out of warranty by now?

Hi Andy,

Its always been like this but it's getting worse now. Everything else works perfect but I feel as if I have no control over the boom movement when it comes to anything like fine work.

The warranty ran out September just gone

 

[Richard Hunton]

You'll need to post a video to YouTube then embed it on here.

Give this a try please

 

[Andy Gaffer]

Mine was nothing like that, you get the back and forth rocking as any machine will do as it settles down but yours are in the rams, will it do it at less revs or in a different power modes? Its as if the check valves are opening and closing before it settles, I can't remember or not if one of the fitters from the dealer where I bought the machine from mentioned that they had to remove the check valves to solve a issue on another machine.

 

[Komatsu]

The warranty ran out September just gone

Has/was it mentioned to your dealer??...if so, and the issue hasn’t been resolved, regardless of the warranty running out it is/will be classed as “an on going” problem. Had an issue in the past with one of my machines, which ran out of warranty during the “fault finding” and that is how komatsu put it to me, “on going problem”, your covered.

 

[V8Druid]

Give this a try please

does it do that on a fixed rev setting Rich? your pump is up-stroking as you engage the motion which isn't helping ..... it also 'looks' almost like structural flexure at the base pins of the rams ????

 

[Richard Hunton]

Mine was nothing like that, you get the back and forth rocking as any machine will do as it settles down but yours are in the rams, will it do it at less revs or in a different power modes? Its as if the check valves are opening and closing before it settles, I can't remember or not if one of the fitters from the dealer where I bought the machine from mentioned that they had to remove the check valves to solve a issue on another machine.

It does it constantly, nothing I change makes a difference, dipper in /out.
Full bucket / empty.
Revs .

 

[Richard Hunton]

Has/was it mentioned to your dealer??...if so, and the issue hasn’t been resolved, regardless of the warranty running out it is/will be classed as “an on going” problem. Had an issue in the past with one of my machines, which ran out of warranty during the “fault finding” and that is how komatsu put it to me, “on going problem”, your covered.

It was indeed mentioned to them, they suggested bleeding the check valves or altering pilot pressures.

The first has been done the latter not.

I need to go back to them now I know this and see what they say.

Thanks for the info.

 

[Mark]

I would first try removing the check valves from the boom circuit to see if the fault goes away.

 

[Andy Gaffer]

So your saying, for example, if your grading stone using the cutting edge you get this bobbing/bouncing as soon as you start to move the boom and stick together?

 

[Richard Hunton]

does it do that on a fixed rev setting Rich? your pump is up-stroking as you engage the motion which isn't helping ..... it also 'looks' almost like structural flexure at the base pins of the rams ????

It does mate. All revs , and work modes.
There is a minute amount of "slack/wear" in the boom foot pin.

That said, (I'm not sure if it's clear in the video) the ram must bounce 15-20mm. Within itself. Which translates into 6inches at the dipper end.
Another side effect it that it impossible to pull a level cut . It looks like a ploughed field.

 

[Richard Hunton]

So your saying, for example, if your grading stone using the cutting edge you get this bobbing/bouncing as soon as you start to move the boom and stick together?

Exactly that, it's impossible to pull a level cut