Hydraulic filter collapse

[Vinpetrol]

I serviced my 2002 case cx130 yesterday and fitted new exhaust .
When I opened up the hydraulic oil tank I found this .

I completed service and fitted new filters including the hydraulic one .
I thought it might be better to change the oil so I went to do this today .
I started the machine to move it into a better position and I noticed the levers went really stiff once the revs were up , it was actually difficult to move them .
I then drained out the hydraulic oil tank and removed the strainer from the bottom of the tank .
The strainer had quite a bit of the filter in it .
I then changed the pilot filter . This was pretty clean.
There was another filter I’ve never changed before , a cardboard set up below the Pilot filter in this

It’s a cardboard affair , it was choked with bits of filter stuck in its outlet .
Initial thoughts are possible water in hydraulic oil rotted the filters but I’m not so sure now that I have drained the oil the state of it looks quite good .
I’m wondering if a faulty main by pass valve could cause this ? I think mine may be faulty as it can pull the engine down at times if working it quite hard . Could this create enough pressure to collapse the filter like that ?
Any thoughts ?
My plan at the moment is clean out tank , replace all filters and tank strainer as it’s slightly damaged . Fill it with hydraulic oil and try it out .
Then look at relief valve if it may of been the cause .

 

[V8Druid]

bypass valve on your return filter must be suspect to allow the filter collapse like that Vin .... should bypass when filter becomes clogged, not suck/blow the filter apart to allow flow
bet you have a fair bit of debris (hopefully all soft) floating about in the system

 

[Vinpetrol]

bypass valve on your return filter must be suspect to allow the filter collapse like that Vin .... should bypass when filter becomes clogged, not suck/blow the filter apart to allow flow
bet you have a fair bit of debris (hopefully all soft) floating about in the system

It is all soft so far need to locate the bypass valve now

 

[V8Druid]

It is all soft so far need to locate the bypass valve now

mine is in the filter housing on the 'Drema
assembly on the left of the body ... pressure switch on the right of the filter body, tells you if any pressure builds up if filter blocked
main return in foreground and breaker return to the right

 

[Vinpetrol]

mine is in the filter housing on the 'Drema
assembly on the left of the body ... pressure switch on the right of the filter body, tells you if any pressure builds up if filter blocked
main return in foreground and breaker return to the right

View attachment 58356
View attachment 58358View attachment 58357

Mine isn’t located at filter housing at all . I have 2 openings at the top of the tank one has a manual pressure release valve on top of it and the rod inside attached to the strainer and the other opening is the housing for the filter .
Angus suggested it could be the load sense on the main pump. When the pump pulls the engine down it should sense the load and back the swash plates off .
Both make sense in my head . I need to find a way to diagnose it . I’m not sure how to proceed . It would help if I knew where the main pressure release valve was !

 

[Vinpetrol]

I replaced all the hydraulic filters and replaced the oil in the tank . I also fitted a new tank strainer as original had a wee bit of damage .
I then ran it up with all new filters in place . The hydraulics are working but the levers go solid and it’s definitely not right .
I then took the return filter out completely . The machine works as normal again , like it did when the collapsed filter was in place .
For some reason when the filter is in place the flow is restricted to the point it’s effecting the servo side.
Any idea what might be happening ?

Sounds to me like a blockage somewhere that with the filter in place is restricting the oil flow so much that the pump sucked the filter in on itself . Once the filter was collapsed the oil flow was enough for the machine to work normally for ages but when a new filter is put in place , the oil flow is too restricted and then the pump is struggling to get enough oil hence the solid levers .

 

[V8Druid]

I replaced all the hydraulic filters and replaced the oil in the tank . I also fitted a new tank strainer as original had a wee bit of damage .
I then ran it up with all new filters in place . The hydraulics are working but the levers go solid and it’s definitely not right .
I then took the return filter out completely . The machine works as normal again , like it did when the collapsed filter was in place .
For some reason when the filter is in place the flow is restricted to the point it’s effecting the servo side.
Any idea what might be happening ?

Sounds to me like a blockage somewhere that with the filter in place is restricting the oil flow so much that the pump sucked the filter in on itself . Once the filter was collapsed the oil flow was enough for the machine to work normally for ages but when a new filter is put in place , the oil flow is too restricted and then the pump is struggling to get enough oil hence the solid levers .

that is weird ..... is it the correct filter, gauge/flow-wise?
looking at the way it collapsed, it comes in around the outside and returns to tank through the centre, .. unusual
is it in tank Vin or external canister ?

 

[DaveDCB]

Is there a breather on it? I know some machines say replace the tank cap after xxxx hours? Not sure it could cause this kind of thing to happen but it’s got to be the cheapest thing to try?
@Mick-the-fitter ?

 

[Vinpetrol]

that is weird ..... is it the correct filter, gauge/flow-wise?
looking at the way it collapsed, it comes in around the outside and returns to tank through the centre, .. unusual
is it in tank Vin or external canister ?

Hi Buddy , yes it’s inside the first chamber in the tank . You’re correct about how it works . There’s a hole in the floor that the filter sits over so the oil passes from outer to inner . The original collapsed filter was genuine . New ones are aftermarket but from a dealer in NI that know their stuff with these machines .

 

[Vinpetrol]

Is there a breather on it? I know some machines say replace the tank cap after xxxx hours? Not sure it could cause this kind of thing to happen but it’s got to be the cheapest thing to try?
@Mick-the-fitter ?

There is but it’s working as it’s the part that you depressurise the system with as well and it works fine. I was hoping @Mick-the-fitter or @CPS might be able to give me a pointer .
I do think I might have have a relief valve not working correctly somewhere as if you put the boom or dipper to the stops in either direction it’ll pull the engine right down but I just assumed this a sticking valve and I drive it within its limits and its ok to use like that . I don’t think this is related though

 

[V8Druid]

Hi Buddy , yes it’s inside the first chamber in the tank . You’re correct about how it works . There’s a hole in the floor that the filter sits over so the oil passes from outer to inner . The original collapsed filter was genuine . New ones are aftermarket but from a dealer in NI that know their stuff with these machines .

bloody odd fault ... most operate the other way - centre out - your way round has a big area trying to force it's way into a smaller chamber ...... and trying to crush the filter ...... but obviously it's as built so should work fine, unless you're getting high pressure in the return lines -- could try tee-ing a gauge in before the filter and see what you're getting???

 

[Vinpetrol]

bloody odd fault ... most operate the other way - centre out - your way round has a big area trying to force it's way into a smaller chamber ...... and trying to crush the filter ...... but obviously it's as built so should work fine, unless you're getting high pressure in the return lines -- could try tee-ing a gauge in before the filter and see what you're getting???

Maybe it is the other way buddy , but that wouldn’t explain the way it’s collapsed in from outside .

How do hydraulic systems work ? Does the pump push oil to create the pressure and flow or does it suck the oil through the feed pipe , strainer and return filter ?

 

[V8Druid]

Maybe it is the other way buddy , but that wouldn’t explain the way it’s collapsed in from outside .

How do hydraulic systems work ? Does the pump push oil to create the pressure and flow or does it suck the oil through the feed pipe , strainer and return filter ?

sucks it out the tank through the strainer and flows it back in through the return filter, which is under lowish pressure as it's open to the tank ... when you divert oil from the pump to a service - say a cylinder, pressure builds in the cylinder, until the diversion (through the spool) closes the flow off and it then dumps to tank again ... judging by the way your filter got collapsed I'd say the return is around the outside of the filter as you described - pressure built up and collapsed the filter ... doesn't explain WTF it's doing it with a new filter, unless it is too fine a filter to flow enough oil ???????? ... with it out of circuit, everything is fine, so can see it as the only logical explanation ? ... lack of clear, unimpeded flow ??

EDIT - thought - does your filter have a stop end and which way up are you installing it? - the centre of the filter needs to be open to the tank port

 

[Vinpetrol]

sucks it out the tank through the strainer and flows it back in through the return filter, which is under lowish pressure as it's open to the tank ... when you divert oil from the pump to a service - say a cylinder, pressure builds in the cylinder, until the diversion (through the spool) closes the flow off and it then dumps to tank again ... judging by the way your filter got collapsed I'd say the return is around the outside of the filter as you described - pressure built up and collapsed the filter ... doesn't explain WTF it's doing it with a new filter, unless it is too fine a filter to flow enough oil ???????? ... with it out of circuit, everything is fine, so can see it as the only logical explanation ? ... lack of clear, unimpeded flow ??

EDIT - thought - does your filter have a stop end and which way up are you installing it? - the centre of the filter needs to be open to the tank port

The filter is open both ends . Just for the avoidance of doubt I will install an oem filter and new breather but I really believe the issue is a restriction of some sort but I can’t think where

 

[V8Druid]

The filter is open both ends . Just for the avoidance of doubt I will install an oem filter and new breather but I really believe the issue is a restriction of some sort but I can’t think where

way I see it Vin, the only restriction is the filter itself as the flow is fine 'til it gets to that then collapses the filter ..... wonder if your swash plate isn't throttling down, when load is removed - assume that machine is load sensing VDP - and the filter is getting a massive flow trying to go through it? the VDP at idle/off load is a minimal flow in comparison --- blockage in load sensing line/circuit holding pressure 'praps

 

[Vinpetrol]

way I see it Vin, the only restriction is the filter itself as the flow is fine 'til it gets to that then collapses the filter ..... wonder if your swash plate isn't throttling down, when load is removed - assume that machine is load sensing VDP - and the filter is getting a massive flow trying to go through it? the VDP at idle/off load is a minimal flow in comparison --- blockage in load sensing line/circuit holding pressure 'praps

All that makes sense but then why would the levers be stiff when the new filter is in

 

[V8Druid]

All that makes sense but then why would the levers be stiff when the new filter is in

back pressurising some where? - like the return line circuits .... what provides your servo pressure .. reducer circuit or separate pump - Mine have their own 35bar pumps directly driven off the motor's timing gear .... if the T line is pressurising with back pressure from the main return it may be possible for it to end up in the T line to the servo circuit ???? and possibly be an even greater pressure than the servo circuit - 's got the main pump doing it

 

[DaveDCB]

Have a read of this, makes sense!

https://www.autocare.org/docs/default-source/communities-files/fmc/bulletins/96-2-diagnosing-hydraulic-filters-with-collapsed-center-tubes#:~:text=The%20two%20main%20causes%20of,to%20relieve%20excessive%20differential%20pressure.

 

[Mick-the-fitter]

Is the suction strainer clean?

 

[V8Druid]

Have a read of this, makes sense!

https://www.autocare.org/docs/default-source/communities-files/fmc/bulletins/96-2-diagnosing-hydraulic-filters-with-collapsed-center-tubes#:~:text=The%20two%20main%20causes%20of,to%20relieve%20excessive%20differential%20pressure.

can't see a faulty by pass having much to do with the issue as the filter is brand new, so the by-pass shouldn't operate .... but worth a look ... the bypass should never operate, until the filter blocks, or no point in having the return filter