Closed center hydraulics quest

[Dirtyho]

I was looking at a jd 3 bottom plow for my 5520 it says it must be used on closed center hydraulics will this work on my tractor. I'm not familiar with the term. Thanks for any help

 

[oldnslo]

Closed center means you tractor has a variable volume pump that maintains a constant pressure in your system with no flow. When a valve is opened the pump will now produce flow.

Is this one of the JD hydraulic rest plows? If yes double check with your dealer to see if your tractor will work with this plow.

How the hydraulic reset works: The rest feature is connected to one of the remotes on your tractor and that lever is locked to keep constant pressure on the reset cylinders.
When you hit a rock causing one of the bottoms to trip your tractor must be able to absorb this oil quickly to allow the cylinder to retract (bottom trip) and then once past the obstacle the hydraulic pressure returns the bottom to the working position.

When these plows were released years ago some of tractors they were used with would not absorb the oil flow from the plow and they blew things up. Hoses, cylinders, etc.

 

[aczlan]

Does it have a control valve on it? If its just the standard lift cylinder, it wont care if your tractor has open or closed center hydraulics.

The difference is that with open center hydraulics,the fluid goes around and around without making much pressure until a valve is opened.
With closed center hydraulics they make max pressure all the time but generally use a adjustable pump which only pushes enough fluid to keep the pressure up.

Per Tractordata (TractorData.com John Deere 5520 tractor information) your tractor has open center hydraulics.

Aaron Z

 

[Tx Jim]

With closed center hydraulics they make max pressure all the time but generally use a adjustable pump which only pushes enough fluid to keep the pressure up.Aaron Z

Actually JD CC hyd systems if working as designed build up the pressure to stand-by psi which is normally 2250#s and then the pump continues to turn but not pump oil as the pistons are moved away from the throw on the hyd pump shaft.

 

[Tx Jim]

I was looking at a jd 3 bottom plow for my 5520 it says it must be used on closed center hydraulics will this work on my tractor. I'm not familiar with the term. Thanks for any help

What is the plow model #?

 

[J_J]

I was looking at a jd 3 bottom plow for my 5520 it says it must be used on closed center hydraulics will this work on my tractor. I'm not familiar with the term. Thanks for any help

Hydraulics:
Type: open center
Capacity: 10 gal [37.9 L]
11.5 gal [43.5 L] (PowrReverser)
Pressure: 2800 psi [193.1 bar]
Valves: 2 to 3
Pump flow: 15.9 gpm [60.2 lpm]
Steering flow: 6.6 gpm [25.0 lpm]
Steering press.: 1900 psi [131.0 bar]


If you use an open center on a closed center hyd system, it may work, for a while.

The small hyd pumps on a CC system are not designed to work full force and pump large amounts of fluid at high pressure for long periods of time.

As long as the OC valve is in the system, the pump is pumping fluid through the OC valve to tank.

 

[Dirtyho]

Thanks for the info I called the dealer he said stay away it will blow stuff up. Ill keep looking thanks to all for the input. No sure of the model # f325