Volvo EC210LC, Hydraulic problems pump no 2

[GudumH]

Hello everyone.

I bought a used Volvo EC210LC excavator, from 2000, which has some problems. !! :-(

Maybe you can help.

1. Right belt motor does not respond when stepping on the pedal. However, if you swing / bend slightly with the left joystick, it will pull well with about 25% force. !!!

2. In the right joystick, the piston for the bucket does not work, and it only has power when it is to lift the entire arm. and no force when pushing the arm into the ground / or lifting the machine, for example.

As I see it, the right belt, the piston to the bucket and the two lifting pistons, all on pump 2, are closest to the engine. so maybe the pump controller doesn't work for pump 2. But then I just think it's strange that it seems to have full power when it has to lift the whole arm. !!

But if pump # 1 can somehow deliver oil to lift the pistons, it makes sense why it can lift the whole arm !

 

[uffex]

Good day
When you lift the boom while using the tracks you will connect both pumps to the track motors, from your description I suggest some seriouse trouble shooting befor you condem components.Begin from the motors and work backwards.
Kind regards
Uffex

 

[funwithfuel]

I would suggest, first thing check your control pressure to both pumps. You have negative control on that machine. You should see about 30-35 kg at each control valve. As you stroke either lever or stick, you drain that oil proportionally to the stroke of the lever until you're at 0 . I don't think you have a problem in the MCV , your functions are working just weak. Boom up works, but requires 2 pump flow. So when you ask for boom, you're stroking both pumps. Pump 1 or 2 may very well be doing all the work. Let's not focus on tracks until you've reestablished your bucket control. Do you have gauges and the ability to T into the circuits? That's gonna make all the difference in the world.

 

[GudumH]

Thank you very much for your response.

That is, I must mount a gauges on each of these two hoses with a T, market in the picture?

 

[GudumH]

This is the diagram, for bucket !

And I wrote wrong earlier. It's PUMP no 1, I suspect for not working!

 

[funwithfuel]

That top circle, yes, the other , I can't really tell. But that top inboard hose is, I believe, where you want to see what is going on.

 

[GudumH]

That top circle, yes, the other , I can't really tell. But that top inboard hose is, I believe, where you want to see what is going on.

Hi

( Pump # 1, closest to the engine, which does not work ) It shows 200 psi (14 kgf) when the engine is idling and when you pull the handle the pressure drops to about 75 psi (5 kgf)

(Pump # 2 (which works), between pump 1 and servo pump ) about 500 psi (35 kgf) when the engine is idling and again about 75 psi ( 5 kgf ) when pulling in the left joystick.

 

[GudumH]

New picture

 

[funwithfuel]

So, we have to start tracing the hose going to pump 1 from the main control valve. If possible, remove both ends of the hose and blow through. I suspect some debris may be trapped.
Your signal should be equal to pump 2. In fact pump 1 , with only 200 psi should be partially stroked. The engine should be loaded a bit.

 

[GudumH]

The engine is not loaded at all, :-/

You don't think I should remove the controller, and control if its okay ?

 

[funwithfuel]

I don't like to open pumps and controllers until we've verified that there is no outside influence. Plugged / pinched hoses, plugged passageways etc stuff like that. Those pumps are very reliable, its usually something much more simple.
Can we check pump standby pressure? What pressure is sitting at idle with no demands.

 

[GudumH]

Pump #1 210 psi All the time
Pump #2 400 psi standby and max 4500psi

 

[funwithfuel]

Can you switch control lines between the 2 pumps?

 

[GudumH]

I have tried that, didn't make any difference

 

[funwithfuel]

No difference, where? Did the pressure follow the hose or stay at the regulator? If pump1 kept low pressure with pump 2s control line, then I would agree, it's time to go after the regulator.

 

[GudumH]

I have attached a picture.

Under the pumps is a valve block, with a solenoid valve inside.

Can it affect the problem?

 

[funwithfuel]

yes , kinda. That's a proportional control valve. check mA at the plug. It really only drops the displacement when engine is under severe load. Prevents bogging down and stalling of the engine. I don't think it's specific to front pump. I believe it acts on both. I'm still concerned with the oil available at the MCV to the pump controllers.

 

[GudumH]

Hello again

Now I just got time to try something new.

I have changed the hoses on the two pumps, so that pump 1 now works as pump 2 and pump 2 as pump 1.

Everything that did not work before, works now, the shovel etc.

and conversely, all that once worked does not work now.

So now I had thought about swapping the regulators around. ???? to find out if it is the pump or regulator that is teasing.

 

[funwithfuel]

Are you saying that by changing hoses, the problem moved? If so, your pump is fine. Look to your hoses from the MCV going to pump regulators. Check for debris and obstructions. Physically remove the hose and blow through it from end to end.

 

[funwithfuel]

Do you have a pattern change valve behind the cab?