Jinma Hydraulic FEL valve leaking when rear 3 point linkage arms lifted

[stgraham]

I have a Jinma 554 with a ZL40 FEL. When I lift the rear 3 point linkage arms, hydraulic fluid starts leaking out of the FEL valve. If the rear arms are lifted to their maximum height, then hydraulic fluid really pours out at a great rate. Has anyone any idea why this might happen and how to fix it?

if the rear arms are left in mid position or lower, there is no leak. Irrespective of the leak, the FEL works fine.

I'm not sure if I need to replace the FEL valve or if it's forcing its way out because of a lack of pressure relief or something??

 

[EE_Bota]

Others will likely be along who know your tractor. Mine is a 304, and could be right much different, but I am not sure.
On mine, the circuit is reservoir>pump>FEL valve>lift unit(reservoir.)
If yours is the same, so far all we know about yours is at some pressure, your FEL valves leaks. We don't know for sure this is because of a relief problem with the lift, all we know is that there is a leak in the valve body in the "tank" gallery of the body (most likely.) You should be able to tell a lot about where the leak is coming from..is it a spool leaking, or a block to block O-ring gone bad? Mine has the block type stacked sections...and each section has a group of 0-rings to seal each block to the next.

For now, unless you demonstrate that the pressures are going above recommended system pressure, then you have to assume your problem is where the leak is, not elsewhere.

 

[RonMar]

I will take a guess that the leak on the fel valve is from the end of one or more of the spool valves? There are usually "O" rings at the ends of the spool valves to contain leakage. There are basically two kinds of control valves, some that are designed to have a low pressure return to the reservoir, and some that are setup for power beyond and can feed a high pressure device such as the 3PH lift. As an example, the prince 5000 series control valves have a 500 PSI pressure limit on the return port, unless they are configured with a power beyond port to deliver higher followon pressures to the next valve downstream. Not knowing the specs on the FEL valve, we will probably never know exactly what followon pressure the valve is rated for. How do I know this? The prince loader valve I had was plummed wrong with that 500 PSI max return port connected to the 3PH. Bouncing a heavy brushhog around one day killed the FEL valve Orings... In learning about this I also determined that the relief valve back in the 3PH control valve, which is adjusted with shim washers, was set way in excess of 3000 PSI. So when I was working the 3PH with a heavy brushhog on it, the system pressure was peaking over 3000 PSI which was being felt on the 500 PSI max return port on the fel valve.

SO in your case, I would say you need to determine what the relief pressure is on your 3PH control valve. On mine it was easy as it had a auxillary putput port with a quick connect on it designed for a dump trailer I think. I put a gauge on a quick connect and plugged it in then sent fluid to that port using the 3PH valve. Then I could set the relief to the proper system pressure. As to your leak, the end caps and control linkage end of the leaking spools should come off fairly easy with an allen wrench. Once the ends are off, you should be able to see the Orings that need replacing. Perhaps a dollar in parts for 4 rings and about an hour of your time...