JCB 4CX swing stalls after filter change

[Earthgoliath]

I recently changed the hydraulic filters on my JCB 4CX as part of the regular maintenance, but now I'm having a problem. The swing only moves to the left and then locks up. One of the hoses has a steady flow, but the other one is completely dry. I've cleaned the reliefs, and the spool appears to be in good shape. Could this be an issue with the internal valve body?

 

[Guav444]

@3arthgoliath this kind of issue is very common after a filter change. usually the cause is air getting into the system. It sounds like one side of your swing motor or valve body isn't getting a solid column of fluid, which could be from a big air bubble.
Even if you think you've bled it properly, sometimes air can get trapped. Try cycling the function back and forth (or in your case, just to the one side that works) multiple times to see if you can work the air out. Also, double check that the new filter is properly seated and sealed

 

[7blackalps]

@3arthgoliath this kind of issue is very common after a filter change. usually the cause is air getting into the system. It sounds like one side of your swing motor or valve body isn't getting a solid column of fluid, which could be from a big air bubble.
Even if you think you've bled it properly, sometimes air can get trapped. Try cycling the function back and forth (or in your case, just to the one side that works) multiple times to see if you can work the air out. Also, double check that the new filter is properly seated and sealed

Thanks for sharing this! I'm looking into getting a used JCB, probably a 3CX and trying to learn what issues to expect. I didn't know a simple filter change could cause air problems like that.

Does this kind of thing happen often with the 3CX too? And when you say "cycle the function," is that something I can do from the cab, or does it need tools?

 

[d0ugg.348]

I recently changed the hydraulic filters on my JCB 4CX as part of the regular maintenance, but now I'm having a problem. The swing only moves to the left and then locks up. One of the hoses has a steady flow, but the other one is completely dry. I've cleaned the reliefs, and the spool appears to be in good shape. Could this be an issue with the internal valve body?

I'd suspect the problem is likely in the main control valve for the swing since the swing works one way but not the other. I'd first double-check the pressure relief valves for the swing circuit for any lodged dirt. Also try gently tapping the valve body with a soft hammer while someone operates the swing control. This can sometimes dislodge whatever is blocking the spool. If that doesn't work, you'll likely need to open up the valve body to inspect and clean the spool itself.