Volvo EC15B swinging problem by arm move down

[v8druid]

might not be a broken spring allowing oil to by pass ..... when you pull on the stick you are allowing oil into the up motion pipe to compensate/fight against the oil which the ram is losing and stop the ''sinking''

as you say it does not do it when the check valve is in place .... so must be down stream of the check valve

Two choices ... as I say ..... the main spool or the servo control of the main spool .... if servo circuit then it must be holding the main spool open slightly.
If main spool .... damaged or something holding it open perhaps ... or not closing properly

[wowe]

Now I must engage myself with the hydraulic components. But there are some questions. In the pic you can see the hydraulic valves of the arm and the dipper. I expected, that they are equal. But this is not the case:


Hydraulic boom dipper.jpg

At the left side you see the main-valve of the boom. At the right side the one of the dipper.

At the dipper control the components "60" are present twice and so the same. Question 1: What is this? a Piston?
At the boom control the components "50" are also present twice.


At the dipper the components "61" are also present twice. Question 2: what´s this?
But at the boom control, the components "53" and "51" differ. Question 3: What can you say about this components?

If I disassemble the boom control, I hope that the hydraulic block can stay together. I think the components "53", "51" and "50" can be extracted without a further disassembling.

Regards wowe

[v8druid]

53 and 61 look like balanced pressure release valves to me

a bit like this one





not sure about the other items ...... difficult to see the detail in the pic

do you have a schematic for the circuits???

[wowe]

#53 and upper #50 are located in the "boom up" main-valve section.
#51 and lower #50 are located in the "boom down" main-valve section.

But I wonder that #51 and #53 differ!?!?!?! (The dipper section is the same at both sides)

#49 is the pre-steering Connection.

#55 - I dont know...

do you have a schematic for the circuits???

I have a schematic with the hoses from the pre-steering to the steering-block. But I think this contains no additional Information for us.

[Muz]

They'll be shock valves

[Mattir]

I made a video:

Hi,

if you take a closer look ar your video an look how your hands are moving, you will find the answer. Put the dozer blade down behind the machine and it will dampen the swinging or rocking.

I've beeb digging with my '15 for some 50+hours and getting a bit more familiar with the controls. They are rather sensitive and because the machine sit on short tracks, it will rock.

Another hint, be careful when rotating with boom and arm extended with full bucket as the machine might tilt. Always have solid ground where you park an ensure that by driving a couple times back and forth to compact.

My machine is XTV and I like the wider track width.

Read about the ram seals and I quess need to take at least the bucket ram out and service the seal or have it fixed as it stretched out while i had it parked

happy digging, gutes graben

[wowe]

@Mattir

I think you didn´t read the whole thread. The jerking Problem has gone by removing the boom drop valve. It was no operator-failure.

[wowe]

SO - new Facts. I made some Trials:

1. I moved the boom up and down. What I have noticed:
If I move the arm slow down and go then back to neutral, then the sinking rate is small and about 1cm/5s.

2. If I moved the boom fast (if the Joystick is moved more to front there is a stronger movement after passing a Special Position) ang go then back to neutral, then the sinking rate is higher and about 1cm/s.


3. I supperted the boom in high Position. Then I removed the lower hose and closed the lower port of the RAM (the port of the RAM which the oil is pushed in for Lifting up) by a blind plug. Then I removed the Support of the boom. The boom was absolutely fix. I waited 15 minutes and the boom was in the absolutely same Position. That means that the internal RAM seals are absolutely ok.


4. I removed also the second hose of the RAM. Then I started the engine. The Joystick was in neutral Position, but on the hose which is fixed to the "down side" of the RAM, there was a massive flowing out of oil. I dont know, if this is normal. If this flowing out has pressure, then it´s no wonder thet the boom moves down.


Thank you for your further help.

[Mattir]

@Mattir

I think you didn´t read the whole thread. The jerking Problem has gone by removing the boom drop valve. It was no operator-failure.

@wowe,

I read the whole thread, but wanted to comment on that vid.

Glad that you solved the problem. I might have the same issue but still suspect myself as the main source :)

[wowe]

remark to the Point 4:

4. I removed also the second hose of the RAM. Then I started the engine. The Joystick was in neutral Position, but on the hose which is fixed to the "down side" of the RAM, there was a massive flowing out of oil. I dont know, if this is normal. If this flowing out has pressure, then it´s no wonder thet the boom moves down.

The conclusion

If this flowing out has pressure, then it´s no wonder thet the boom moves down.

is wrong.

The oil can only flow in the area above the Piston of the hydraulic-cylindre, if the stering valve of the lower side lets the oil flow out of the cylindre. If the valve of the lower side is closed, no oil can flow out of the area below the Piston and because oil is incompressible, no oil can flow in in the upper side and the boom doesn´t move down.

[wowe]

Hello,

I´ve got my new Trailer, so I can start with excavating. Today I made a interesting observation: when the digger boom is moving down with neutral Joystick Position and I push the driving sticks, then the sinking disappears. Has somebody an idea about this effect? I will buy a pressure gauge for further Investigation.

[wowe]

I need some Information about the pressure gauge kit. It contains 2 gauges and I must select the pressure range for them. Can anybody make a suggestion?

[v8druid]

Hello,

I´ve got my new Trailer, so I can start with excavating. Today I made a interesting observation: when the digger boom is moving down with neutral Joystick Position and I push the driving sticks, then the sinking disappears. Has somebody an idea about this effect? I will buy a pressure gauge for further Investigation.

you've got pressure bleeding into the circuit some how ... faulty valve in the main block and bypassing into the boom lower circuit

[v8druid]

I need some Information about the pressure gauge kit. It contains 2 gauges and I must select the pressure range for them. Can anybody make a suggestion?

70 and 400 bar .... the smaller gauge will do your servo pressures and the larger one will do your main pressures

stauf test point kit
http://www.ebay.co.uk/itm/Hydraulic-...oAAOxy3NBSeLfo


minimess test point kit

http://www.ebay.co.uk/itm/3818261924...84.m1436.l2649

[wowe]

I bought the lower one... ok - I will order with 70 and 400 bar.