B2710 Hydraulic Relief Valve adjustment

[GhostRider29]

Hello Kubota folks,
I have a few question. I am trying to adjust the psi on my B2710 HST, as the FEL and 3PH felt weak. Before I start with the questions, I want to give a little background. I replaced all rubber hoses, o-rings (that I could locate on the workshop manual), hydraulic fluid strainer, hydraulic fluid and filters. The B2710 has a Bush Hog FEL on it there are no quick connectors between the control stick and FEL, just the two hoses one is outlet and other one inlet. I unplugged the quick connector between the outlet port and control stick and plugged in the pressure tester on the end from the outlet port. The relief valve setting pressure (factory spec.) should be 1920-1991 psi. I got a hydraulic pressure tester from Amazon for Kubota B, BX, L… series. The original shim was kinda worn out. There was only one washer and one 0.2 mm shim. The psi reading was around 1,200 psi. I replaced it with a set of two new washers (as suggested from the workshop manual) and one new 0.2 mm shim. The pressure went up to around 1,550 psi. I took out the new 0.2 mm shim and replaced it with one 0.4 mm. The psi when up to around 1,800 then dropped to 1,200 suddenly psi. I have no idea why it did that. Before I changed from 0.2 mm to 0.4 mm shim, the 3PH with ballast box would lift at low rpm with no problem. Now it won’t with the thicker shim. I read somewhere that it is normal. I tested the FEL after taking out 0.2 mm and putting in 0.4 mm and it’s a lot stronger but I wonder why the tester shows low psi reading. Is there something wrong or is it normal? Lastly, is there a better way to connect the tester other than the outlet port?

 

[North Idaho Wolfman]

First off your using the wrong term in your thread title.
As the HST Relief valve has NOTHING to do with hydraulic system pressure, they are different systems.
I'll change the title.

You are getting erroneous readings because you're measuring it wrong.
You can't disconnect a power supply loop and put a gauge on it like that.
You need to put the gauge on an output to the loader cylinder.

Also, I'm betting since you have an aftermarket loader on it, that that loader valve will also have a relief valve on it.
You'll need to set both reliefs to get it to work properly.

 

[GhostRider29]

First off your using the wrong term in your thread title.
As the HST Relief valve has NOTHING to do with hydraulic system pressure, they are different systems.
I'll change the title.

You are getting erroneous readings because you're measuring it wrong.
You can't disconnect a power supply loop and put a gauge on it like that.
You need to put the gauge on an output to the loader cylinder.

Also, I'm betting since you have an aftermarket loader on it, that that loader valve will also have a relief valve on it.
You'll need to set both reliefs to get it to work properly.

Thanks for your response and editing the title. I was going to edit the title as it’s just a habit to add HST because when I do search online on B2710 the term HST tends to come up after B2710. I don’t mean the relief valve on the HST.
Yeah I thought about connecting the tester to the output hose that goes to the loader cylinder. Will I still have erroneous reading because the other cylinder (other side) will operate at the same time?
For the loader relief valve, I am sure it’s located somewhere on the valve (control stick) housing? Should I put the 0.2 mm shim back in and take out the 0.4 mm shim?