i'm hoping to find an owner of a JD870 (or 770/970 i believe are the same) who has one of the following: the rear hydraulics package, a backhoe or ideally a front snow plow blade who can tell me which ports JD is using for the output and return lines as we have tried everything.
in detail.. our situation...
we currently own a JD870 which does not have the rear extension/power beyond kit nor any additional hydraulics from stock. we have the rock shaft lift and that is it. this past fall we wanted to install a hydraulic lift snow plow. we managed to snag a JD plow off a similar tractor (required minor frame alteration but almost a bolt up) and found an aftermarket cylinder and a directional control control valve (input dumps into output except when lever is activated in which case it then pushes into one of the two ports going to the cylinder for up/down). we had no luck getting it to work so delved a bit deeper.
after ordering a hydraulic flow meter (why are they so expensive.. we got lucky on that big auction site) we discovered our pump was not the best (it was original and we had noticed our rockshaft being sluggish and not staying up) and after installation had great pressure from pump the pump output but could not get any more than 25lb at the rockshaft test port. since then we have replaced all the o-rings on the pressure relief valves (one seal was missing on the main relief... from before we bought the tractor apparently...) and finally installed a new o-ring on the rock shaft piston which helped much and now it holds and can lift 2 people fine. with that fixed... we decided to try hooking up the front plow again.
what we have tested and know:
-with the plow input connection disconnected the rock shaft operates fine. i'm not sure if pressure is up to spec but performance on the rock shaft seems to be notably better.
-if i connect the input of the control valve up to the port to the left of the rockshaft case block (which seems to be directly connected to the input via a 90 degree space) the rockshaft stops working (my thoughts are given the valve type we are just getting all the pressure relieved down into the reservoir). the rockshaft does work if i pull on the lever for the front plow and operate the rockshaft lever at the same time (most likely since its blocking the flow through the control valve normally has). if i have weight on one side or the other i can get the one with no weight operating (which makes sense if i'm basically putting a tee in a hydraulics flow diagram but isn't what i want).
-if i connect up to the right side of the block below the rockshaft pressure relief (the test port) i get nothing.
-connecting the return line to the rear left and front left ports instead of the reservoir does not improve things .
mostly i had four main questions
1... am i connecting up to the correct port for pressure out to aux attachments? from what i can tell i am.
2... am i connected up to the right return ports
3... am i missing something in order to have each lever (rockshaft and front blade) operate without touching the other lever or being affected by the others weight (basically how to make both systems work at once)
4... am i using the correct type of valve for the front bucket (directional control valve. flows input->output when not in use and flows input->portA/portB when lever is in A/B position to operate cylinder.
if anyone has pictures of the hookup, diagrams, etc that would be most helpful. i've looked and have found diagrams for the rear aux connections and they *seem* to suggest the port in the front i use for pressure is correct and the one behind it is for return (but that doesnt seem to work). i have seen the JD backhoe manual and it just states to connect up to existing rear aux connections (helpful i know...).
in detail.. our situation...
we currently own a JD870 which does not have the rear extension/power beyond kit nor any additional hydraulics from stock. we have the rock shaft lift and that is it. this past fall we wanted to install a hydraulic lift snow plow. we managed to snag a JD plow off a similar tractor (required minor frame alteration but almost a bolt up) and found an aftermarket cylinder and a directional control control valve (input dumps into output except when lever is activated in which case it then pushes into one of the two ports going to the cylinder for up/down). we had no luck getting it to work so delved a bit deeper.
after ordering a hydraulic flow meter (why are they so expensive.. we got lucky on that big auction site) we discovered our pump was not the best (it was original and we had noticed our rockshaft being sluggish and not staying up) and after installation had great pressure from pump the pump output but could not get any more than 25lb at the rockshaft test port. since then we have replaced all the o-rings on the pressure relief valves (one seal was missing on the main relief... from before we bought the tractor apparently...) and finally installed a new o-ring on the rock shaft piston which helped much and now it holds and can lift 2 people fine. with that fixed... we decided to try hooking up the front plow again.
what we have tested and know:
-with the plow input connection disconnected the rock shaft operates fine. i'm not sure if pressure is up to spec but performance on the rock shaft seems to be notably better.
-if i connect the input of the control valve up to the port to the left of the rockshaft case block (which seems to be directly connected to the input via a 90 degree space) the rockshaft stops working (my thoughts are given the valve type we are just getting all the pressure relieved down into the reservoir). the rockshaft does work if i pull on the lever for the front plow and operate the rockshaft lever at the same time (most likely since its blocking the flow through the control valve normally has). if i have weight on one side or the other i can get the one with no weight operating (which makes sense if i'm basically putting a tee in a hydraulics flow diagram but isn't what i want).
-if i connect up to the right side of the block below the rockshaft pressure relief (the test port) i get nothing.
-connecting the return line to the rear left and front left ports instead of the reservoir does not improve things .
mostly i had four main questions
1... am i connecting up to the correct port for pressure out to aux attachments? from what i can tell i am.
2... am i connected up to the right return ports
3... am i missing something in order to have each lever (rockshaft and front blade) operate without touching the other lever or being affected by the others weight (basically how to make both systems work at once)
4... am i using the correct type of valve for the front bucket (directional control valve. flows input->output when not in use and flows input->portA/portB when lever is in A/B position to operate cylinder.
if anyone has pictures of the hookup, diagrams, etc that would be most helpful. i've looked and have found diagrams for the rear aux connections and they *seem* to suggest the port in the front i use for pressure is correct and the one behind it is for return (but that doesnt seem to work). i have seen the JD backhoe manual and it just states to connect up to existing rear aux connections (helpful i know...).
