BX Hydraulics - 101 and maybe more?

[dragoneggs]

I haven't paid much attention to the workings of the hydraulics system on my BX25D ever since my purchase. I have about 400hrs on it. Yes, I have done all the maintenance per schedule but now I am thinking of doing two things... add a 3rd function for a grapple and boost the pressure. As such, I thought it would be nice to know everything there is to know about the Kubota BX hydraulics system. So... educate me!

P.S. I know I could do some researching and reading on my own but this is more fun and opinionated!

 

[ultrarunner]

I checked the pressure at about 50 hours and found it low...

Had a jar of small stainless fasteners and found some very small washers...

Used one to shim the spring and it bumped up the pressure right to the high end of the range... the difference was most noticeable...

 

[Dave M7040]

Step one is to get a gauge and fittings so you know what the pressures are.

Less than $25 at most hydraulic shops. Bring one of your quick connects so they provide a matching one.

Get a short piece of hose on it if viewing the gauge is not going to be easy to see.

If you have a rear remote, plug the gauge in, throttle wide open and then send pressure to gauge and read.

If you are going to buy a grapple I assume you at least have a FEL.

I don't know the BX series but on the larger M series, the hydraulic flow goes first to the FEL valve and then out through a power beyond port on the FEL valve to the 3 pt and rear remotes.

What this means is that is the relief valve on the FEL is set low then the rear remotes and 3 pt will have their pressures limited by the FEL valve There is a second relief valve for the rear remotes and 3 pt.

I don't recommend elevating pressures beyond the spec'd value as you can over do it and start breaking and bending loader arms for example. Search for bent loader arms and you will see a number of people whose loader no longer sits flat on the ground.

You want to have WSM for the tractor and loader so you are not stumbling around in the dark.

Dave M7040

 

[Tractor Seabee]

I haven't paid much attention to the workings of the hydraulics system on my BX25D ever since my purchase. I have about 400hrs on it. Yes, I have done all the maintenance per schedule but now I am thinking of doing two things... add a 3rd function for a grapple and boost the pressure. As such, I thought it would be nice to know everything there is to know about the Kubota BX hydraulics system. So... educate me!

P.S. I know I could do some researching and reading on my own but this is more fun and opinionated!

Mark, if I tried to explain it here on TBN you would be bored silly by the time I got done and I would have typewriter cramps. I was able to understand it pretty well by going through that section in the WSM. If you haven't got it yet, what are you waiting for, under $100. Dennis may have one in stock.

Boosting the pressure is easy, remove the left rear tire and the valve is right in front of you. The WSM has the part numbers. Probably will have to order them. 1mm equals around 39 PSI. If I was still unpacked from the move; I have some somewhere. They are cheap so bought an array of thicknesses.

I do not know Kitsap's policy on mail. I buy all my parts from Jennings in Puyallup. Small items they mail to me in USPS PM packages and charge my account. K will not drop ship.

Ron

Ron

 

[dragoneggs]

Thanks Ron and Dave. Okay a specific question... can I increase the lifting ability of the FEL w/o affecting the BH hydraulics?

 

[ultrarunner]

I found raising the pressure affected loader and backhoe...

The 10% boost to the high spec was really noticeable.

I do agree higher pressure can add component stress and the BX Loader I have is a single cylinder for loader dump and this design distributes stress differently than having double cylinders with each at the pivot points.

More lift also adds to front axle stress... I also keep the hoe on 99% of the time for counter balance.

Moving sacks of concrete mix I can transport heavier than I can lift.

 

[Tractor Seabee]

Mark, raising the pressure is equal across all attachments. Why worry about the BH? It will lift bigger logs/rocks. It is somewhat faster on the controls but you get used to it. I just lower the RPMs if I want to move slower. I seldom get over 2200 RPM for any thing as I find the movements smoother.

Ron