Volvo EC20B XTV Hydraulic Issues

[TickTock]

Evening.
Im new to this forum and I'm hoping you guys and gals can help me out on a few issues.

From the beginning........
I purchased this Volvo off Ebay. we needed a yard machine pronto to load stone and fill bulk bags, it is a 2002 2700hrs?? cabbed and was no vat, just the ticket.
I collected it , it started, tracked straight, didn't sound or look to bad. the seller said it has been stood for about 5 years. he put new filters on it and gave it a jet wash.
Worked it in the yard, not hard work just loading stone and soil. perfect.

Then bit by bit i started to notice the following:
Hyd Pump cavitating. (ordered Filter/strainer/oil) but was fine after 10mins warm up.
Dipper arm (intermittently) would not come all the way in towards cab. (thought it was just a valve sticking)
Left had controls were sloppy, had a look, uj pin had snapped so put an M6 bolt in, not as sloppy now.
Boom ram weeping (found nick on ram!)
Dipper ram started to leak
When you bought the boom up and left the dipper in the totally upright position i could get out the cab and push the dipper arm backwards by hand..
Boom drops really quick
If you lift the boom right up, point the dipper arm towards the sky, the boom starts to drop, then if you pull back on dipper control the boom will start to come back up, not fast but it does move back.
Dipper ram has started to bump half way through its travel, this started after it was re-sealed (has been bench tested) and new Hyd Filters/oil was put in.
Hydraulic pump/engine labours when lifting boom/dipper.
Blade drops quickly but not all the time, generally with pump running rather than overnight. (Different Issue to the above?)
All of the above happens with no load, just bucket and hitch on.

I hope the above makes sense. Im hoping you can point me in the right direction.?

Ive got a list of what I've done so far, Do i start to list this now or wait for a nod?? Thanks

[Muz]

Can you see any frothing of the oil in the tank ? the oil should be clear at all times .. welcome BTW

[TickTock]

Hi Muz, Great to hear from you . No, no frothing at the moment, the only time it did is when the rams/cylinders went back on, but this cleared and settled down. Hyd oil /filter/ strainer filter have all been changed,
Using Pennine Hyd oil 46 A7F3 at the moment , before that i was using Morris liquimatic HV46 (i think ??!)
Thanks

[Muz]

Hi Muz, Great to hear from you . No, no frothing at the moment, the only time it did is when the rams/cylinders went back on, but this cleared and settled down. Hyd oil /filter/ strainer filter have all been changed,
Using Pennine Hyd oil 46 A7F3 at the moment , before that i was using Morris liquimatic HV46 (i think ??!)
Thanks

Trapped air would explain some of your issues but if theres no froth we can discount that. Your oil grade is a bit thick, AWS 32 is the correct one for UK which might explain your engine labouring especially in cold conditions. On many machine of age .. oil bypassing seals in rams is normal after a while so you can expect to replace those seal sets one by one to eliminate problems .. some of which you have done I see. Dozer blade dropping will be orbital valve seals, which at that those hours I would not expect at all . Its hard to envisage all your problems as you describe without a video or something .. create your self a channel on a vid sharing site then link us to it with a walk round

[TickTock]

Thanks Muz,, i will change the Hyd oil to 32 and report back.

[Muz]

Thanks Muz,, i will change the Hyd oil to 32 and report back.

Well I'm not saying it will cure all your problems but that machine has a VD pump IIRC so if its frosty in the uk. the engine will struggle to move thicker than correct specified oils unitl the oil warms up a good bit

[TickTock]

understood, I'm with you on this, the Pennine 46 seems really heavy (the Morris 46 is a lot thinner and a pretty blue colour!) and its what i had at the time , it will do it no harm swapping it to 32

[TickTock]

VOLVO EC20B UPDATES

GOOD NEWS,

Today ,.. Changed hydraulic oil to Pennine HVI T32 grade, emptied the 46 grade out filled with 32 ran it round the block, emptied the Hyd tank again, then put more fresh 32 in.
There is a notable improvement, when you drop the armrest you can hardly tell the pumps kicked in, before you could feel the engine straining. no frothing at all.

Stauff test point adaptor has arrived, hooked the gauge to the end of the valve block, revs up, dead ended the blade, bucket, boom etc. got a reading of 190bar each time as per Volvo spec.

BAD NEWS,

No improvement on dipper arm ram. ill try and explain bellow.

When you push the dipper arm away from you the ram is hesitating about halfway through its stroke. Almost as if its battling pushing the oil back.

When you bring the dipper arm towards you it struggles to get past the 12 o'clock position, it sort of just locks up, but the weird thing is if you get out the cab you can push it away from you by hand and the re-locks in that position. you can trick it to come all the way back by either pulling the controls right back or releasing controls then pulling back again but it seems a real strain.

Boom arm, lets say the bucket is 6' of the ground, you pull SLIGHTLY back on the boom control to lift the boom, However the boom drops until you really pull back on the controls. Another oddity is that if you pull back on the dipper controls at the same time to push the dipper away this counteracts the boom dropping and you can actually lift the boom this way as well.

I have already opened up the easiest ends of the spool valves for the dipper and boom ( i think I've traced them back correctly but will double check) the springs are intact on this side, i didn't want to delve any further as I'm not up to speed on valve blocks. one thing i did notice,,,, with the 2 spool caps off and the Check Valve? and bung removed from above the spool valves, lets say you push the dipper spool in should you see any oil run out of top hole above the boom spool ? because it does,, are all of these top journals connected ?? or have i got a problem??

Im hoping the above makes some sense??

[Muz]

VOLVO EC20B UPDATES

GOOD NEWS,

Today ,.. Changed hydraulic oil to Pennine HVI T32 grade, emptied the 46 grade out filled with 32 ran it round the block, emptied the Hyd tank again, then put more fresh 32 in.
There is a notable improvement, when you drop the armrest you can hardly tell the pumps kicked in, before you could feel the engine straining. no frothing at all.

Stauff test point adaptor has arrived, hooked the gauge to the end of the valve block, revs up, dead ended the blade, bucket, boom etc. got a reading of 190bar each time as per Volvo spec.

BAD NEWS,

No improvement on dipper arm ram. ill try and explain bellow.

When you push the dipper arm away from you the ram is hesitating about halfway through its stroke. Almost as if its battling pushing the oil back.

When you bring the dipper arm towards you it struggles to get past the 12 o'clock position, it sort of just locks up, but the weird thing is if you get out the cab you can push it away from you by hand and the re-locks in that position. you can trick it to come all the way back by either pulling the controls right back or releasing controls then pulling back again but it seems a real strain.

Boom arm, lets say the bucket is 6' of the ground, you pull SLIGHTLY back on the boom control to lift the boom, However the boom drops until you really pull back on the controls. Another oddity is that if you pull back on the dipper controls at the same time to push the dipper away this counteracts the boom dropping and you can actually lift the boom this way as well.

I have already opened up the easiest ends of the spool valves for the dipper and boom ( i think I've traced them back correctly but will double check) the springs are intact on this side, i didn't want to delve any further as I'm not up to speed on valve blocks. one thing i did notice,,,, with the 2 spool caps off and the Check Valve? and bung removed from above the spool valves, lets say you push the dipper spool in should you see any oil run out of top hole above the boom spool ? because it does,, are all of these top journals connected ?? or have i got a problem??

Im hoping the above makes some sense??

Well your dipper is wired wrong for a start , pulling back on the stick should pull it towards you

[TickTock]

Apologies, the controls are correct, just my scribbled notes are incorrect , i will double check the actions of the dipper that causes the boom to lift .

[TickTock]

UPDATE.
Been back to the volvo today. everything is as before, confirm that when you try to lift the boom slowly, the boom immediately drops, if you push the left hand controls forward the boom and the dipper starts to rise together, if the dipper is as far it will go then just the boom rises. all of this happens without any further movement of the right hand controls.

ALSO. after running through the above scenario a few times, noticed the the dipper cylinder was warm/hot,, but both the boom and the bucket ram were cold ?? Is this a bypass symptom ??

Any ideas would be greatly appreciated . Thanks

[Muz]

UPDATE.
Been back to the volvo today. everything is as before, confirm that when you try to lift the boom slowly, the boom immediately drops, if you push the left hand controls forward the boom and the dipper starts to rise together, if the dipper is as far it will go then just the boom rises. all of this happens without any further movement of the right hand controls.

ALSO. after running through the above scenario a few times, noticed the the dipper cylinder was warm/hot,, but both the boom and the bucket ram were cold ?? Is this a bypass symptom ??

Any ideas would be greatly appreciated . Thanks

Shouldnt be any heat generated unless work is being done .. think youve got some plumbing issues.. might be on the pilot side and not the powered side.. these are a real problem to solve without the valve block schematics .. you'll need to refer to volvo for those i'm afraid