Backhoe attachment on JD4120

[tlm720]

New member here. Thought I'd share my new attachment. Mounted a Bobcat 709 backhoe on a 4120 JD using the subframe for a Woods backhoe and some custom fab work. Not quite the hoe as the JD 93 I had on my 1010 crawler loader, but already taken out 4 trees and their stumps with it. Now I'm not sure how I lived without it.

 

[buffdan]

New member here. Thought I'd share my new attachment. Mounted a Bobcat 709 backhoe on a 4120 JD using the subframe for a Woods backhoe and some custom fab work. Not quite the hoe as the JD 93 I had on my 1010 crawler loader, but already taken out 4 trees and their stumps with it. Now I'm not sure how I lived without it.

Looks great..
More details needed
Did you use the tractor hydraulics?
Pictures of custom fab work, attachment to the subframe?

Ease of attaching and detaching ?

Dan

 

[tlm720]

My tractor has power beyond but not the optional diverter valve for the power steering pump flow so I'm running 12 gpm. Backhoe is plenty fast. Uses the Woods 4 point so it goes on and off in a few minutes. I'll get some photos of the fab work when I get home. Basically I cut the Woods backhoe side of the subframe to nest into the area on the backhoe where the quick tach fit and welded it in place. Also had to trim the backhoe side frame so it didn't hit my tires.

I added some images showing what I did. The red line on the subframe is where I cut it. The red line on the backhoe is where the subframe fit up and welded. The yellow lines on the backhoe are where I cut the backhoe. This was just a good image of the quick tach on a 709 backhoe that I found on the internet for demonstration purposes. I'll get a photo of the my unit with the subframe attached and add it to the thread.

I also removed the safety valve on the backhoe that disabled the backhoe hydraulics if it came unattached from the Bobcat loader and switched the QDs over to what fit the tractor. There was a short safety chain that I removed as well. Bobcat had some incidents where people were getting injured when these backhoes came disconnected causing crushing between the backhoe and the skid steer cab.

 

[tlm720]

Here are some photos of the actual work. It's been very hot here lately so I did not get around to removing the hoe to get these shots until it cooled off some. You can see the subframe on the tractor as well as how and where the subframe is welded to the backhoe. Visible in one photo is the piece I cut off from the subframe (2 places) to make it fit. Also visible is the third point attachment that I created on backhoe. I was using the hoe on my three point while awaiting the subframe from Woods.

It took six minutes to put it back on the tractor. Obviously it would take another minute or two to remove the 3 point arms had those not already been off.

 

[buffdan]

Thanks for the details.

Very nicely done.. Good planning and fabrication.

I have a Davis D100 backhoe which is currently attached to my trencher, which I am considering adapting to my Kubota.
Your technique is what I also might do.
The Woods subframe is incredibly expensive though..

There is a great thread here by dfkrug on making your own subframe.. Though buying the Woods subframe saves a lot of fabrication..

Thanks for sharing

Dan

 

[tlm720]

I agree that the Woods subframe is pricey. I am a mechanical engineer and manager of metal fabrication shop. I thought about designing my own in Solid Works and having all the pieces laser cut and welding it up at home. If I could have gotten ahold of a cad model of the tractor I would have. I figured the hard part was making it fit the tractor and Woods did that part already. I saved enough on the backhoe I decided to go this route. I wish I would have looked at the price of the Deere subframe though.

 

[tlm720]

Been working on my new garage and getting some use out of the backhoe.
https://www.youtube.com/watch?v=6MBK5Axh934&feature=youtube_gdata_player

 

[arlen4720]

but not the optional diverter valve for the power steering pump flow

What do you mean by this?

Hoe install looks great.:thumbsup:

 

[tlm720]

It's a mistake. I thought I remembered in the video that came with the tractor it talking about a diverter to combine the flow of both pumps for use with the backhoe. I think I was confusing it with the diverter for the directing the front scvs to the rear. Never the less, I ordered a selector valve today to accomplish this. It will give me a full 17 gpm to the backhoe (and no power steering while I'm digging)

 

[arlen4720]

It's a mistake. I thought I remembered in the video that came with the tractor it talking about a diverter to combine the flow of both pumps for use with the backhoe. I think I was confusing it with the diverter for the directing the front scvs to the rear. Never the less, I ordered a selector valve today to accomplish this. It will give me a full 17 gpm to the backhoe (and no power steering while I'm digging)

I'm not sure that will work real good. The power steering pump system pressure is 1500 compared to the 2500 of the implement pump. On the eHydro model, the PS pump supplies internal lubrication, and charge pressure to the hydro tranny, plus it circulates oil through the cooler.