Volvo EC15B swinging problem by arm move down

[wowe]

So - the Problem with the wrong test set is fixed:

Stauff-Testset.jpg

I tested immediately, if it fits - well itīs the right one. Hydrotechnik UK has taken the wrong one back without any trouble, although it was my fault. When the heavy coldness disappears I will start to analyze the problem with the down moving boom.

[v8druid]

So - the Problem with the wrong test set is fixed:

[ATTACH=CONFIG]3463[/ATTACH]

I tested immediately, if it fits - well itīs the right one. Hydrotechnik UK has taken the wrong one back without any trouble, although it was my fault. When the heavy coldness disappears I will start to analyze the problem with the down moving boom.

Haven't you got any tee adaptors with that set

[wowe]

Haven't you got any tee adaptors with that set

I got exactly what I have ordered. Itīs a low cost Version. I have three test points which I can make a measurement and that will work. If I really need a T-adaptor then I will buy it later.

[wowe]

I got exactly what I have ordered. Itīs a low cost Version. I have three test points which I can make a measurement and that will work. If I really need a T-adaptor then I will buy it later.

I need an editing possibility later than 5 minutes after finishing a thread, because my english is sometimes bad.

I have three test points where I can make a measurement and that will work.

Only yet some years to go and I will be a really Oxford english writer

[Mattir]

Wove, I think we are using here a rare subset of Oxford English: the excavator English

[v8druid]

I got exactly what I have ordered. Itīs a low cost Version. I have three test points which I can make a measurement and that will work. If I really need a T-adaptor then I will buy it later.

I need an editing possibility later than 5 minutes after finishing a thread, because my english is sometimes bad.

I have three test points where I can make a measurement and that will work.

Only yet some years to go and I will be a really Oxford english writer

or you could have said " I have three test points which I can make a measurement" at

or

"I have three test points, at which I can take a measurement"

I think we each have an equally complex mother tongues Wowe

[wowe]

Ok boys and Girls - now the time has come the problem must be banished. I Need your help, because you are the hydraulic expert and I am a hydraulic beginer. But because I become a car mechanic and an electric engineer I will overcome with the problem - if you will help me with your experience.

A short recall of the problem: The boom was sinking down in neutral joystick position. The seals of the RAM are tested and rated as ok. While playing with the hydraulics I noticed, that the sinking of the boom is stoped if I execute another hydraulic movement. Letīs take a view to the valve of the boom:

Ventil_Arm.JPG

This behaviour could apply to a defect check valve (right below in the pic) at port A: If this check valve donīt close then the oil will flow back in the tank and the boom sinks. If I activate a additional hydraulic Funktion, the pressure in the flow-back pipe increases and the counterpressure stops the sinking down.

So I will check the check valve.

Here it is:

ArmVentilAnheben.jpg

My workflow:

Step 1: Boom/dipper sink down to ground
Step 2: Depressurize the System (Ignition on/armrest down/moving the Joysticks in all directions)
Step 3: Put on safety glases, gloves. I have no especially hydraulic gloves, but thick leather oneīs.
Step 4: Not necessary, but I do it: Measurement of the pressure at the control block with a Manometer to go sure the system is free of it.
Step 5: Removement of the check valve. Because the oil-Level in the System is higher than the area of the valve, I expect that oil will leak. To prevent this is not easy. Either I must bleed the whole System - but I didnīt read this anywhere or I must produce a vacuum in the oil tank by a pump. Whtīts the right way to remove this valve and not leaking oil?

So - now I need your input.

wowe

[v8druid]

what the hell is the non return/check valve for Wowe, with an open to tank line on one side of it?

what is the A6 port connected to?????

you can try and introduce a vacuum to the tank, but will have to stop off all the open to tank connections first i'd have thought?
might just be easier to drain it down

[wowe]

what the hell is the non return/check valve for Wowe, with an open to tank line on one side of it?

look at the drawing I have added: in the right lower area you can see the check valve. This valve is a "flow in" valve to prevent cavitation.

what is the A6 port connected to?????

The post A6 is the "boom up" pressure section.

might just be easier to drain it down

Hmmm - I was afraid that this should be done...

[v8druid]

flow in to where ? the pump?
can you not put up the whole schematic?

[wowe]

can you not put up the whole schematic?

I do only have this. Look to the check valve. "A" is the line to the RAM with the "boom up" tap. and "T" is the return line back to the tank.

[v8druid]

that check valve is a pretty strong candidate for the fault then Wowe ....... but damned if I can see WTF that check valve is even in circuit for??

[Muz]

but damned if I can see WTF that check valve is even in circuit for??

Thats because it might be a 'shock' valve, and not a check valve ?

[v8druid]

can't see how that's anything other than non-return valve, with that symbol Muz and only two connections

[wowe]

Itīs an anti cavitation valve. Thatīs the technical term.