How to adjust hydraulic pressure?

[oldafretired]

Just got a pressure gauge from KennyD (Thanks KennyD!). Tested my L3901 off one of the FEL connectors and the pressure was only 1800 PSI at 2500 RPM. That seems kind of low. Anyone know what the recommended pressure is and how to adjust the pressure?

 

[kennyd]

I'll copy my reply from the OTT forum:

According to the Kubota specs page: http://www.kubota.com/product/L3301/L3301.aspx


The system pressure is 165 kgf/cm2 which converts to 2346 PSI (why can't they just say that!)

I can't help on the adjustment, but if it's under warranty I'd be calling the dealer. If you going to do your own wrenching, then the factory tech/service manual would be a great investment.

 

[oldafretired]

Thanks!!!!

 

[Tx Jim]

To raise hyd system pressure one needs to turn pressure relief valve on frt end loader valve in until 2346 psi is reached. IMHO as long as system pressure doesn't exceed 2346 psi then warranty if avaialable shouldn't be affected

 

[LD1]

I believe the L3901 adjustment would be the same as the older L3800 and L3400 series tractors. There is a plug that you remove down by the hydraulic filter on the bottom. This plug will have a spring under it. You increase the pressure by adding shims between the plug and spring, I think most use a #10 machine screw washer. I'll see if I can find the thread, there was a pretty lengthy one that discussed it

 

[LD1]

Here you go http://www.tractorbynet.com/forums/kubota-owning-operating/128908-bump-up-lift-capacity-l3400.html

Long read, but I think somewhere in there someone has attached pics, as well as how much x.x mm shim increases psi by.

An important trick though, put a shop vac in the fill port for hydraulic fluid. It will draw a vacuum on the case and you will only loose a drop or two of fluid doing the modification