Hi I recently had my hydraulic cylinder for my grapple bucket repacked and now it does not extent with any power. I apologize for any incorrect terminology I am new to heavy equipment. Background I recently bought a 2004 NH LS170 and with it came a single cylinder grapple bucket. Upon receiving the LS170 the grapple was strong (could easily move multiple railroad ties and pull them together and pickup multiple), however there was a small leak in the front seal of the cylinder so I decided to get it repacked. I used it a little and it blew a hose before the repack (if i remember correctly it was slow to open the grapple, retract the cylinder, but powerful on close, cylinder extension). I then got a new hose and took the cylinder for repacking. The cylinder was repacked and was very weak on extension (close of the grapple) so I returned to where it was packed and it appeared the piston oring gave out. It was repacked but the problem persisted, I went back and was assured that this time the pack was good (took apart and orings were fine). The problem that exist is that the grapple is powerful on open (cylinder retraction) but slow and very weak on close (cylinder extension) (which may be the reverse of how it was when I originally received the grapple). It can no longer move a single railroad tie let alone close hard enough to pick them up. I have tried to bleed the cylinder on install (tilted grapple down left the back hose cracked and watched as air and foamy hydraulic fluid came out while tapping the cylinder and then closed the system once the fluid appeared to no longer have air). Do i need to bleed both lines? I have attached a picture of the cylinder for reference (it is a single cylinder grapple with the cylinder sitting in the middle). Any help would be hugely appreciated.
Try swapping hose connections for the skid steer to make sure it's not a loader issue. Probably will need to remove flat face connectors from hoses to swap.
I've tried the hose in both configurations. The one configuration I get no movement of the cylinder
Piston put back on the rod backwards or the piston seals installed wrong/damaged. Far fetched perhaps bit the way I see it is that its the variable that changed.
Would the piston being backward cause the power to flip like explained above. Power was with close now it's with open
Probably not directly cause it
Is the control moving the spool in the control valve fully.
That was coming to be my next step to check if the valves are operating correctly. If there was an issue with the valve staying open or staying closed could that cause the symptoms I am seeing? (Again that the cylinder not moving when hooked up correct with flow to the rear and return in the front and being able to actuate the cylinder in reverse but having no power with the opening of the cylinder )
That doesn't seem quite right. If a cylinder issue should not change at all. If loader side should obviously switch. Does your loader have the Faster couplers,( push to release pressure) like all newer machines? If not sure post a pic. Reason I ask, these couplers have an internal o ring for the push to release feature, and a leak there will result in pressure bleeding off.
I believe they are faster couplers pictures attached Thanks for the help
You didn't by change smash a hose between the arms /coupler. I did and it would only flow one direction. A good visual will tell the tale
I don't think so but I'll look
Any other thoughts
What style of gland nut is on it. That is the end the rod extends from. Those small cylinders are fairly easy to take apart.
Well some good news switched the hoses back to the correct inlets and sprayed the valve levers with some wd40 and now we have slow grapple open (cylinder retraction) and powerful grapple close (cylinder extension). So I can at least work with it