This might be one for the dealer to figure out. Well worth the $250 insurance deductible.
Either way, thanks for your effort on this.
Issues with loader dump after overpressure/blown line L5460
- Thread starter CdnSldr.ret
- Start date
Either way, thanks for your effort on this.
I was able to find the hydraulic schematics in the service manual. I’m convinced the issue is with the load check valve not fully operating.
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Yes, I looked at that yesterday. As I suggested remove and inspect it. Its just a one way poppet.
Unfortunately, if its damaged replacements are NLA. I know in the past components (poppet??) from other valves have been successfully swapped in.
Dan
For completeness for anyone else viewing this thread in the future, this is the location of the load check valve.
I know this seems like a possibility but its a reverse flow check on the pressure out port. Your tests show that port is working fine. I can not visualize how the load check could block the return port.
Dan
Dan
It has been a few years since I’ve had to read hydraulic schematics, but the load check operates in the return circuit does it not? Supply pressure actuates the load check to allow return flow.
No. The load check operates on the pressure out port.
Example:
When the loader is in a raised position pressure in the lift work circuit is held by the glands on the spool. They block both ports.
If the spool is shifted to further extend the cylinder the glands are repositioned to divert pump flow to the output port and simultaneosly open the return side.
The load check valve keeps the pressure port shut until pump side pressure builds and exceeds the existing pressure if any in the work circuit. At that point pump pressure forces the check valve open and flow goes to the cylinder. This prevents any held load from sagging as the port transitions to open and pressure builds.
Dan
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A rather anticlimactic end to this thread!
Kubota diagnosed the issue as being with the male QC for the dump cylinder rod end. They replaced all four QC and this was covered by insurance.
The way I tested the QC flow-through was certainly flawed. Using a flow gauge would have been best, or I would have needed to operate the circuit for much longer (which was difficult as it was making a mess) to properly assess if there was a flow restriction.
Either way, thanks for the help @TheOldHokie!
Kubota diagnosed the issue as being with the male QC for the dump cylinder rod end. They replaced all four QC and this was covered by insurance.
The way I tested the QC flow-through was certainly flawed. Using a flow gauge would have been best, or I would have needed to operate the circuit for much longer (which was difficult as it was making a mess) to properly assess if there was a flow restriction.
Either way, thanks for the help @TheOldHokie!