Adding additional SCV's to JD 4720

Where is the Backhoe return?

Kennyd,
'First post, I've been out here learning from you guys for quite some time now... What a great resource!

OK, I am working on the same upgrade on a 2008 JD 4720. I'm installing the PB kit and using a Prince Wolverine WVS21BB5C1 2 spool valve with the PB adapter to achieve the 4th and 5th SCV functionality. I understand the serial nature of the PB circuit, the need for a low pressure return to a sump and the valve used is very clear on how it is plumbed. Everything has made sense to me up until I came across this post. I was confused about something you said in the quote below and was hoping someone could clarify.

Kennyd said:

Once the valve is mounted you will need to get two 1/2" hoses and the proper QD's to be able to plug it into the PB lines. You will NOT use the return port that the backhoe plugs into since that bypasses the 3PH, but rather the one that's used when you remove the backhoe. You should have one Male and one Female QD.

Click to expand...

What are you referring to when you say not to plumb to the return port the backhoe uses? Is this the one just below the drivers right, rockshaft arm and part of the PB kit? I don't have a backhoe to reference and the above comment on the backhoe return makes me go hmmmmm...:unknown: These things are too expensive to risk screwing up when knowledgeable help is a question away!

If I'm OK using the transmission return port that's available after the PB installation, does anyone know what the standard is for the 3/8" QD? It doesn't mate to a spare 3/8" ag interchange QD I have and I'll need to know when I get hoses around. The QD is on the tractor miles from my house, so measuring with the calipers is a stretch.

Thanks for all the help!
Matt

Thanks for clarifying!

KennyD,
Thanks for the clarification on the return - I was worried I had missed something big. My PB kit was shorted 2 fitings so I'm waiting for those and my bracket to mount the valve. A week or so and I'll have it buttoned up.

I'll post a pic or two when its "finished"... version 1.0 will have hoses. After I catch up on my stump grinding before the grass grows, I'd like to convert to hard lines. In the mean time, I have a great deal of work to do (mostly in the seat after the hydraulics are ready).

Thank you for the lead on the ISO designation for the return male QD. The QD's for the SCV's and PB are all 1/2", but the PB return is a 3/8" on the 4720.

I'll post more when I get things ready and a can provide a pic of the tractor hydraulics and a "before" pic of my once beautiful ash forest, now reduced to acres of ash stumps and firewood (the emerald ash borer is coming if it hasn't already gotten to you).

Thanks again! :thumbup1gif:
Matt