I would assume that the valve bank goes with the backhoe, correct? As long as you don't move any of the valve control levers, the pressure is confined to the hoses between the valves and the cylinders under load (except any small amount of leakage through the valve).
Any pressure that is in the supply line from the tractor should be able to be relieved by actuating a non-supporting circuit such as the swing cylinder.
If you do relieve the pressure from the supply hose, again, as long as all the control valves stay closed, the cylinders are not going to move anywhere.
I have had similar issues with the front loader, but there the valves do stay with the tractor. I had parked a trailer wheel on one of the bucket teeth. I figured I could connect the loader and simply pull it out from under the trailer. The pressure in the bucket curl cylinder, however prevented making the quick-connect mate.
The JD quick-connect tips turned out to be rather fragile. The tapping the end trick worked to remove the pressure, but it also removed the tip spring retaining clip.
The lift cylinder connector had been replaced twice already due to the clip failing during actual use. When the spring clip fails, the tip is no longer able to open the other side of the connection on the tractor, and no flow happens, so the loader stops moving.
I ended up making a modification to the failed connectors - I put two small nuts inside of it to hold the valve tip spring in place when it was screwed back on. Now, the tiny little fragile retaining clip is not an issue.
On a safety note, I would recommend lowering the unit to the ground prior to disconnecting the hoses as described in the instructions posted. Some kids might think its cool to play with the control levers and might manage to cause the unit to tip over on themselves, etc.
You can always use the hydraulics to raise it back up and align it with the quick-connect after reconnecting the hoses.
- Rick
