New guy with a question???

[Gundog]

Hi I am new here I recently purchased a new Kubota B3300SU tractor with a loader and backhoe. I also have a brush hog type mower and a 5' box scraper. This is my first tractor but I have operated equipment of different types for many years.

I ordered the mechanical thumb for my backhoe and now I would like to make it hydraulic operated getting on and off the tractor to adjust the thumb is a pain. The thumb must be pinned out of the way to dig and I have been digging out a lot of small tree and brush stumps it would be so much handier to be able to operate the thumb hydraulically.

Years ago I worked as a forklift mechanic and I have worked on many hydraulic systems but I don't know much about the Kubota system.

What I am not sure about is where the best place to tap into the hydraulic system to power the new thumb cylinder. My first thought was to T into the supply and return lines since the system already has a bypass built in. My thought is to use a solenoid valve with a momentary toggle switch to operate the thumb.

I have a small machine shop so I plan to machine some parts to mount the toggle switch to one of the joy sticks maybe even in the grip. I don't really want to add another handle to the existing valve because I don't think there is room in the small console that houses the controls for the backhoe.

Any thoughts on this would be appreciated. I plan to go talk this over with the dealer that sold me the tractor to see what they think.

Thanks Mike

 

[Burtonbr]

I've seen a few threads, mostly on TBN about converting a static thumb to hydraulic, I suppose you could do it with a diverter, just like third function on a loader, but I've seen most just add another valve to operate the thumb in series with the BH valves.
This thread has a little info, in post #7 Squidget has a link to his album showing some good pictures of his.

 

[bandaidmd]

Useing a solenoid valve might get complicated because you have to have a two way system to operate the ram in~out.
A diverter valve is electricly controlled with a in and out port for 2 way operation
https://www.surpluscenter.com/item.asp?Item=9-7852

that is the one I'm going to use for my bucket grapple.

I would think by adding this into your bucket curl curcuit with the switch on the handle that controls the curl would be pretty easy to get the hang of.

The basic way this works is you would take the hoses that come from the valve ( you will have to have short jumper hoses made) and go to the curl ram and attach them to the in on this valve then take the hose that you unhooked and put them in the ports on the opposite side of the valve. The new hoses to your new ram on the thumb go into the other ports. As long as your not sending current to the solenoid on the valve everything works as normal , when power is applied it "diverts" the fluid to the new ports so the same lever that you used to curl now operates the thumb. Since it blocks the original ports when in divert mode your bucket should hold whatever position it was in.

 

[gpreuss]

It is a whole lot easier and more cost effective to simply hose in another valve in series. All Kubota valves are open center, allowing fluid flow in the neutral position. Make sure you get the same type of valve - most common valves are - and this should be a piece of cake. Find the pressure line to the backhoe, disconnect it and hook it to the "IN" side of the new valve. Run a new hose from the "OUT" port of the new valve to where the pressure hose used to go to the backhoe. Add a couple of hoses from the control ports of the new valve to your thumb cylinder.
Your local hydraulics supply person will be delighted to fix you up with the right hose ends and adapters. I'd guess this will be about $300. including the cylinder, valve and hoses.