Kubota vs. John Deere

[1Lawman]

I have a 2012 John Deere 5093E. I've always had Kubota's in the past..I see a lot of differences in hydraulics but I don't understand them well..My JD has open center hydraulics..Not sure what the Kubota M9960 or my old M8200 but besides much more power I notice the hydraulics of the Kubota run MUCH cooler..Can someone tell me the differences and tell me what JD gets in the way of trade off (other that speed) that Kubota gives up ? What is rockshaft hydraulics and why does my JD hydraulics run at 180 degrees Farenheit? Pros and cons ???

 

[Tx Jim]

I think both Kubota models you mentioned are open center at least Tractordata states the M8200 is OC. IMHO the reason the JD OC hyd's get hotter than normal is because oil is leaking through a control valve or relief valve although 180 degrees is not hot for hyd oil. Rockshaft hyd's are the valves and piston that raises the 3 pt and the "piston" can be internal or external or a combination of both types.

JD 5093E hyd flow 22.5 GPM @ 2828 psi while K M9960 is 17 GPM @ ?? psi according to Tractordata.com

 

[1Lawman]

Assuming all three models are open center is the hydraulic pump working continuously on all three?
If oil is leaking through a control valve or relief valve is that by design or would it be a defect?

 

[Tx Jim]

On an open center system the hyd pump pumps oil continuously through a series of control valves to sump and oil is diverted by control valve to each chosen function. Pressure is controlled by relief valves that are supposedly set at system pressure. Oil leaking through a relief valve or control valve(if above specs.) is a defect

 

[J_J]

There are going to be differences on tractor specs, as the engineers try to work out the operating system.

Different pumps, different size hoses and fittings.

Amount of cooling.

Two of the same type tractors might run at different temps.

With the valves in neutral on an open center hyd system, the less resistance to the flow due to hose and fittings will determine some of the operating temp.

Higher engine rpm will cause the pump to pump more fluid.

Overuse of the relief valve will contribute to the heat factor.

A hyd bush hog will impose a heavy load on the hyd system.

I would estimate the average temp to be from 160 to 200 degrees.

Temp of the day will affect the temp of the hyd.

Most have some radiator cooling, and dirty fins may contribute to the heat factor.

The are probably any more reasons for different temps on tractors.

 

[1Lawman]

There are going to be differences on tractor specs, as the engineers try to work out the operating system.

Different pumps, different size hoses and fittings.

Amount of cooling.

Two of the same type tractors might run at different temps.

With the valves in neutral on an open center hyd system, the less resistance to the flow due to hose and fittings will determine some of the operating temp.

Higher engine rpm will cause the pump to pump more fluid.

Overuse of the relief valve will contribute to the heat factor.

A hyd bush hog will impose a heavy load on the hyd system.

I would estimate the average temp to be from 160 to 200 degrees.

Temp of the day will affect the temp of the hyd.

Most have some radiator cooling, and dirty fins may contribute to the heat factor.

The are probably any more reasons for different temps on tractors.

Makes sense...I have in fact noticed the hydraulic lines are warmest on hot days when I am mowing with my Bush Hog 3210 which is a 3 point hitch mower that weighs 2800 pounds..The aluminum lines at the SCV's will get too hot to hold with a bare hand for more than one second..Guessing around 180 degrees which sounds like what should be expected...Thanks