Bleeding air out of Hydraulic system on John Deere 2030

[Gil A]

Have 2030 John Deere with mounted loader. Had leaking cylinder on loader and fluid became so low loader would not lift. Repaired cylinder, installed and system would not lift loader as air had gotten into system. John Deere does not have a bleeder value, manual says use system controls to bleed air. Have been doing it off and on as time permits over 2-3 weeks and still not completely free of air. Originally it took about an hour to raise lift, now have it raising in about 10 minutes. Since had lost a LOT of fluid I drained system, changed out hydraulic filter and replaced with new filter and fluid. Yes, I cleaned the screen. Is there a faster way to get air out of system than just continue operating it? Need to use tractor and don't want to wait 10 minutes for the hydraulic to raise lift.
Thanks, Gil

 

[Tx Jim]

Sounds to me that you have more hyd problems than air in system from repairing a hyd cyl. On good operating hyd system air should be bleed out after cycling cylinders 2-3 times. How long since hyd filter was changed & sump screen checked/cleaned? Has stand-by pressure been checked lately? It should be 2250 psi. What type hyd valve controls FEL?

 

[Gil A]

Yes, drained and changed fluid, filter and cleaned screen. Could see tiny bubbles in fluid after changed fluid and operated lift a few times. Now can not see the tiny bubbles and it is cutting a minute or two off lift time each time operated. Before leaking cylinder problem hydraulic were operating find. Could there be an air bubble somewhere in the system or that the pump is failing all of a sudden?
Thanks, Gil

 

[Tx Jim]

Closed center hyd's are very difficult to diagnose. To correctly diagnose one needs to know both pumps gpm & psi output. I'll ask you again what type valve operates FEL(ind or scv)??? To my knowledge there is no air bubble blocking hyd flow. With 3 pt raised,engine running look in hyd filler hole behind seat for moving oil which would indicate leaking 3 pt control valve seals.

 

[Zebrafive]

Were there any signs of water in the oil you changed? I am wondering if water could have slightly rusted something and causing a problem, like maybe the filter relief valve, surge relief valve or pump crankcase discharge valve. Has the stroke control of the pump been "played" with?


I can't think of a way the system would air lock.