rScotty
Super Member
- Joined
- Apr 21, 2001
- Messages
- 8,258
- Location
- Rural mountains - Colorado
- Tractor
- Kubota M59, JD530, JD310SG. Restoring Yanmar YM165D
Which JD manual is that? I know that JD published a lot of good FOM (Fundamentals of Machine) manuals on their various tractor systems. Is that the type manual you mean? I'd like to add a JD FOM on closed system hydraulics to my tractor library.Going with new valves is the best choice given the age of the machine. I think JD was using Gresen so a direct replacement is no longer available. Rich B1 is correct about the different spools. The JD manual shows that each spool had a different housing.
You can restore operability with aftermarket valves. You will have to fabricate brackets, and potentially make new lines. Also the backhoe will not operate as smoothly as it does with the OEM valve because of what Rich B1 noted above. However it will still work safely, just rough.
You will need a closed center valve capable of the full 23 gpm. Most likely your going to have to get a 25GPM valve.
Why do you say it would need a valve capable of the full 23 gpm? Usually PS has a dedicated priority on a portion of the total flow, so that has to be deducted and doesn't leave a huge amount. As I see it, all that would suffer wiith a lower gpm BH valve would be some continuous high end backhoe speed - which most of us don't use often anyway. In a closed system the pressure reservoir handles any short term call for full flow & recharges quickly.
That takes us back to pressure. In a closed system, pressure is constant and the reservoir means that usable flow doesn't vary (much) with demand. Of course the old JD500 was only 2000 psi.. unless some idiot previous owner turned the pressure up in the last 50 years....Hmmm..... turning up pressure for more power and more problems should be easy for a mechanic type to do and would explain everything, btw. .....Includng the leaking O rings. A simple pressure check would answer that question.
rScotty