Backhoe B26 hydralics bypassing

[J_J]

If you have several reliefs in a circuit, you can set them all the same if the components will take the pressure. The reliefs in the valves are there to protect anything using fluid from that valve.

If there are weaker components down stream, the relief is set for that valve/circuit to protect against higher pressure produced by the tractor hyd pump.

If you are going to talk to someone at the dealership about the hydraulics, it should be the service tech/mechanic. A lot of supervisory people are not qualified to answer tech questions, and will try and BS.

 

[MarkV]

Woody this may help you some. Go to TractorSmart.com is your online source for Kubota online parts. and follow the directions for down loading the B26 parts manual. You don't actually down load it, they send you a PFD file by e-mail so it may take a day. It has pretty good graphics and the part numbers. A handy thing to have around.

MarkV

 

[woody]

great info and thanks alot, I have been out in the shop fixing me up a gauge. I check the pressures myself and came up with 2200psi for the fel and the same on the BH. the next time I talk to the service rep I'll know more about what I am talking about.

 

[mrennie]

The shims to adjust the PRV are under a cap on the bottom of the FEL valve assembly. Even though it is on the FEL valve my understanding is that it controls the max pressure for the FEL, BH, and 3PH. The factory manual procedure for checking it says to remove one of the lines at one of the FEL cylinders and attach your gauge there, then to try curling the loader bucket against the stop and watching what the peak pressure is. Of the top of my head, I can't remember which hose or cylinder they connect to or what the pressure is supposed to be, but I *THINK* it is a bit higher than 2200 PSI. I can check later this weekend if you want (I am out of town right now).

Michael

 

[wdchyd]

you can disconnect any hose from BH controls going to a cyl providing it's not one with a work port relief (that pressure will show up lower)......

 

[J_J]

There is a difference between cracking pressure, and full relief. The cracking pressure will be higher, and when the relief is fully open, the pressure will lower, and this is the pressure you want to adjust.

 

[wdchyd]

There is a difference between cracking pressure, and full relief. The cracking pressure will be higher, and when the relief is fully open, the pressure will lower, and this is the pressure you want to adjust.

I think you got it backwards JJ...
Kubota Flow/Load Meter Test - Tractor Videos - Kubota, John Deere, New Holland and More

This video shows it......cracking pressure is just when flow starts to bypass to tank......full relief shows higher pressure when dumping all flow to tank.....

Max pressure is at full relief

 

[J_J]

cracking pressure

The point at which the internal pressure of a hydraulic system triggers or actuates a valve. Also called the blow-off pressure.

It would seem to me that the initial pressure to move the poppet off the orifice would be greater that full open, which will release more fluid, and decrease pressure.

Perhaps you could explain further.

 

[woody]

yes sir, I think adjusting the fel prv with shims is the answer to my problem. need to know the max pressure and then I need to convince the dealer and Kubota rep to get R done, or I'll have to do it myself. it still bothers me that the service man told me it was 40psi over max and clearly it can't be.

 

[kennyd]

yes sir, I think adjusting the fel prv with shims is the answer to my problem. need to know the max pressure and then I need to convince the dealer and Kubota rep to get R done, or I'll have to do it myself. it still bothers me that the service man told me it was 40psi over max and clearly it can't be.

Can you describe exactly how you tested the pressure?