Volvo EV210 – Arm Cylinder Slows Down After Halfway Hi everyone, I'm having an issue with the arm cylinder on a Volvo EV210. The cylinder extends fine at first, but once it reaches about halfway through its stroke, it starts to slow down noticeably. The first half of the extension is smooth and normal I will tell. After that, the movement becomes progressively slower, like something is restricting flow or causing a drop in performance. No visible leaks, and the retraction works normally. I'm trying to figure out what could be causing this. Has anyone run into a similar problem or have suggestions for diagnosing this further? I attached hydraulic schematic of it. Thanks in advance
I’m sure you have checked your hydraulic fluid?
Is this for an EC210B? Serial number would be helpful and does it have hose rupture valves? What are cycle times for every function?
Yes EC210B, no hose rupture valves. I didn't measured it. When have serial number will upload it, I think something wrong with 4pi pilot pressure it becomes too low or something can it be ?
If it were the arm holding valve I think it would struggle all the way when arm in. You can always tee in a gauge at 4Pi and see. I think what may be happening is that the first half of your arm travel is gravity acting upon your arm and then when needed you are not getting conflux or 2 pump flow. This could be the arm conflux solenoid in the servo valve block or the center bypass valve not shifting.
Yes maybe you are right. How to check arm conflux valve and centre bypass ? Any additional advice?
That's very common on the B and into the C series. Arm regeneration (safety suction) valves limit the flow so that it's not a free fall, at or near the bottom of the arc, the pump takes over for gravity and begins pushing the rest of the way in or out. Totally normal in the arm and bucket circuits. Most noticeable in arm.
Yes but it was faster before that is problem...
Then I would perform a drift test. See if you have internal leakage past the piston. If that checks out fine, I'd be looking at the arm regen. Are you lacking on power in that function? Do you have power throughout the arc? Are you able to stop the arm travel wherever and whenever you want? Or does it continue past your stop point? By the way, I said almost what Ben had stated. Redundant information, my apologies for clouding the water.
Hydraulic cylinder is good already checked. I have enough power on function just it is slower. Arm confux valve I think can be problem but need to find and check it
The solenoid valve for the center bypass is on the servo valve block where the safety lockout solenoid is. This routes pilot oil from the arm in signal to the center bypass valve. It appears you have schematics so you should be able to follow that
Thanks, I don't understand still how oil from left pump will go to arm according this schematic valve 61 will stay open even if centre valve 67 is closed. Bit confusing for me.
61 is just a path for external conflux. There is a hose that connects Po and Pi ports.
Solved problem was pressure sensor on pilot line for arm..