Kubota MX4700 help with plumbing 3rd function valve
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Michael In Tennessee
Gold Member
OK TX Mower, that is, my understanding as well.
Now tell me why the backhoe doesn't have a tank line nor, apparently does this 3rd function valve have three lines.
I am confused.
flkeysff: As far as I can tell, you are hooked up right unless the 3rd function valve has a third port that you are not using. So, the backhoe PB line fit well? I assume you have some extra length tucked away somewhere. If the grapple and FEL are working, then fluid must be flowing. Seems right.
Now tell me why the backhoe doesn't have a tank line nor, apparently does this 3rd function valve have three lines.
I am confused.
flkeysff: As far as I can tell, you are hooked up right unless the 3rd function valve has a third port that you are not using. So, the backhoe PB line fit well? I assume you have some extra length tucked away somewhere. If the grapple and FEL are working, then fluid must be flowing. Seems right.
Michael, I had to purchase a 1/2JIC to 1/4boss orb fitting to make it work but it does fit. Yes I have some hose tucked away. The "P" port hose was supplied with the kit and fit perfect to the PB connection on the control valve. I was not sure if I should have used the "P" or "T" port on the 3rd function valve to connect the backhoe hose??? I am also thinking that I may need to make a short hose to loop the 3rd function lines that go to the grapple when it is not in use? Any thoughts on that?
Michael In Tennessee
Gold Member
Working lines to the grapple can be left dead headed when not in use.
P is always pressure in. T is tank, which is confusing and why I was asking TX Mower questions. But, you have no other choices.
P is always pressure in. T is tank, which is confusing and why I was asking TX Mower questions. But, you have no other choices.
I wasn't sure because I do not know the flow of fluid. If the flow comes from the block under the tractor then I would think all is good, if the flow comes from the "pb" port on the control valve then shouldn't the line back to the backhoe go on "T" and not "P". Maybe I am just over thinking it. I need to hook my bh back up and check to see if and how it works.
TX mower
Bronze Member
Having gone back through the entire thread, see Post 10. Apparently the backhoe may not use a 'conventional series' connection as it disables the 3pt-hitch (3PH) and uses a selector valve. It is not a 'conventional series control valve' providing full Power Beyond to all implements (including the 3PH) at all times.
I strongly suspect that the Land Pride kit you reference in Post 18 contemplates a 'conventional series' system and implements.
I agree with your statement that "P" is pressure IN and "T" is LP Tank Out when talking about a 'conventional series system'; I would never route from "P" or "PB" to "T" in such a system.
So yeah, it's a confusing system with that 'unconventional' backhoe in the loop. I'll withhold further comment lacking a complete understanding of how the hydraulics in this 'hybrid' case work and should be plumbed, other than to say I'd be darned careful to be certain about all of it before powering-up.
IF, through whatever error, one manages to 'deadhead' the pump, the consequences could be both costly and dangerous (something will have to 'give', sometimes with explosive force at over 2k psi).
IMHO just because a line in a kit will 'fit up' in terms of length and port compatibility that doesn't make it correct.
IMHO it's very difficult to know exactly and correctly what everyone is talking about in terms of kits and valves without reference to specific brands and model numbers - Land Pride, for example, makes lots of stuff and any valve manufacturer has many options / configurations to choose from.
Thanks, the line in the kit as per the instructions that came with it say that is where it is supposed to connect. I going to contact land pride after the holiday to see it they can explain their instructions a little better as they say what to disconnect but if I followed them I would no longer have a functioning bh.
Michael In Tennessee
Gold Member
The MX4800, which I have, and I'm sure the MX4700, do not have a selector valve. However, the hoe has only two lines.
The Land Pride kit is specific to the MX tractor series. Everyone uses it, but few have backhoes.
I would think he is OK. Since he has already tested function. If the pump was dead headed, he'd already be screwed.
So here is what land pride said. "Thomas*
The best way to do it is*
Power beyond to the back-hoe.* The return line from the back-hoe goes to the P port of the valve.* The T port will need to go back to the tank.* Please let me know if you have more questions.*
Thanks*
Michael Butler*
Service Coordinator
888.987.7433 Ext. 2723"
Can anyone explain this to me?
The best way to do it is*
Power beyond to the back-hoe.* The return line from the back-hoe goes to the P port of the valve.* The T port will need to go back to the tank.* Please let me know if you have more questions.*
Thanks*
Michael Butler*
Service Coordinator
888.987.7433 Ext. 2723"
Can anyone explain this to me?
MtnViewRanch
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Yes, Michael thinks that you are never going to take the hoe off and use the 3pt hitch again. :confused2: The t port on the 3rd function valve needs to go to the return power beyond port on the hydraulic block. ( The upper left port on the hyd block.) This is what feeds the 3pt system.
