Just got a couple of questions on the hydraulics for my post hole digger. Im using a 3.18 gear box with a Danfoss 6.9 cu motor mounted off the ssqa. I plan on using the power beyond from the backhoe to a valve, then to the motor. The question I have is there is three lines for the Kubota BH 70 backhoe and three lines that can be hooked to the valve P,N,T. Is line T coming off the valve a low pressure line going back to the tank? I believe the line coming back from the backhoe is a low pressure. Thanks
Doing a hyd post hole digger.
- Thread starter Dwiz
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5030
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Sure you have enough flow to spin the motor sufficiently? Don't believe the B series Kubota has enough flow but I could be wrong.
old and tired
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Yes, and that is the only hydraulic line that can have a "T" connector (multiple lines connected together; all low pressure return to tank.)
5030
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When you get it hooked up and working, please let us know how well it works. I sold my PHD and bought a Shaver post pounder, much quicker, no backfill and it will pound RxR ties too.
prichard
Veteran Member
If you bh is end of the line maybe it doesn't have pb. You may have to grab the inlet of the bh valve.
I only have about 50 post to put in. The soil is clay with some rock but when its done I will post pics and maybe a video. I know alot of people have posted on what torque, speed and gpm is needed so were gonna find out. I should complete the project by the end of Feburary.
Comes from the loader through the BH and to the 3 point. I installed the BH and lines and knew the blue line was low pressure just didnt know if the valve was low pressure return.
Sarbatche
New member
Any update on this?
I built this backhoe mounted PHD awhile back works great... here is the thread when i was building it ...hope it helps ...
www.tractorbynet.com
help converting pto phd to hyd phd
I'm in the process of fabricating a PHD to be mounted on the thumb of my back hoe .The tractor is 45 hp with a 14gpm hyd pump~2500psi. The back hoe is plumbed by a rear remote with 1/2" lines . This project is twofold being that when the phd is not installed my intent is to use the new hyd lines...
www.tractorbynet.com
rScotty
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I don't have any specs on the gear box, Danfos motor, or your supply pump - or know anything about that particular Summit Valve so I can't help with that. You may end up using a PTO pump for more flow.
But I do have a couple of comments on your hydraulic design drawing. Nice drawing BTW.
1. The Loader Valve doesn't show a Power Beyond adapter sleeve. The Motor Control valve does show the PB sleeve, ..but it is in the "N"? port. What is an "N? port?
2. Normally both PB ports should be labeled the same on the control valve body, and both require having a PB sleeve to transfer pressure out from the valve. When the PB port is not in use a PB sleeve is not installed and the port is blocked off.
3. It looks like your motor control valve is set up to control two different motors. Is that correct? or does the extra valve handle and hose pair control something else?
4. You have three return lines to the tank. Put some thought into keeping the fluid friction low. You can join them together with Y connectors, but the bottom leg of the Y then needs to be a larger diameter. Don't join return lines using "T" connectors.
Good luck,
rScotty
Yes, just been working on my house and wanted to post but got side tracked. Hyd valve from Summit I am not to impressed with but they work. I changed the spool over to the motor spool and when the valve was apart there was a piece missing. I used summit flat faced couplers and well lets say you get what you pay for. The gear box I got from Messicks is a mule and a half. Nice piece. Danfoss 6.9 motor no problems. 9" bit from Tractor Supply works fine.
So the first design was on the side of the loader bucket hooked to the Kubota third function.This worked fine for the first tests runs and then things got a little scary. If you dont get the loader stick in the detent spot quickly and it stays in the down position as you are digging, your gonna go for a ride that will get your attention real fast. Second test was in solid clay with the third function and loader bucket. I was down about 24/28 inches no problem but when i pulled up to get the dirt out the bit kept spinning very slow and lost all function in the hydraulics. Tried a few thing but nothing would work. I let the machine sit and cool and thank God it went back to normal. Dont care what Neil says that valve got hot and the solenoid stuck.
Third test was to not use the third function or bucket hook up anymore, so I went to Tractor Supply and bought the post hole digger, used the arm and hooked up the hyd valve to the BH lines. This worked very well in clay with an RPM between 35 & 45. I used the hyd calc from Womack Machine and I think it is spot on. I never measure flow from the machine but it definalty does the job. As for down force and rocks its not gonna work but reverse does. I took videos and will link them later but here are some teasers.
Sarbatche
New member
What about mounting it in place of a bucket on the backhoe arm?
It works fine for what im using it for now. I might make the skid steer mount for the front and center the motor with only 1 pivot not 2.
