live hydraulics

Without wanting to cause too much fuss, I was wondering if someone could give us a short tutorial on live hydraulics, what's good, what's bad, what generally get the job done, etc. We just bought a JD 4020 (has 2 remotes), and the hydraulics seem to leak a little (lift action is slow some, but full for power), but I am unknowledgeable about the "live" aspect. Thanks in advance for your time and consideration! Also, what about hdraulic fluid: is it all generic, or is it like car oil, you shouldn't switch brands? What's a good trade name here? When should you change it out? Other maintenance things we ought to do??

The first tractors drove everything from the rear end, after the clutch. This meant if you pushed in the clutch, the hyd pump would stop. They quickly realized this wasn't good, & drove the hyd pumps from a shaft in front of the clutch.

A related issue is live pto - same concept, but it took longer for tractors to get live pto. Was harder to get a live shaft to the back of the tractor....

As someone said, open center vs closed center may be an issue that comes up. JD liked to use closed center, not sure if they did on your model. It affects the types of hyd controls you can add to your tractor. Open center flows oil all the time, unless you move a lever & block the flow, diverting the oil to move your cylinder. Closed center has constant pressure, but only flows oil when it is needed by opening a lever.

Oil - your manual will list a specification that the oil has to meet. You have 3 options; JD brand oil which is more spendy, but some feel they get a better oil going with the OEM; an oil from a fleet & farm supply store that is designed for JD specs; or the same source of oil that is called 'universal' oil and lists in fine print many brands of oil that it is cvompatable with.

Since I have 3-4 brands of tractors & combine, I tend yo get the universal oil that is compatable with many things.

There is universal hydraulic oil, and there is universal tans/hydraulic oil. Big difference in them, many tractors use the rear end gear oil for the hyd sump, and the oil _must_ be good enough to lube those rear end gears. I try to always get the better grade trans/hyd oil so I don't goof & put the straight hyd oil in a gearcase.....

So, you can go to JD for oil, or you can shop at any farm supply store and get a compatable trans/hyd oil.

--->Paul

Open-center vs closed-center is another question you may come across soon. I don't know which system your tractor has. Open-center means that the hydraulic pump will always pump the same amount of volume (gpm) regardless of how much demand there is. Closed-center is (in my impression) a better design. This setup only pumps as much oil as the system needs to maintain pressure. So if you are not using any hydraulics, the system will not be moving any oil, this saves on horsepower, fuel, and reduces puts less heat into the hydraulic oil. Sadly most manufacturors have gotten away from this type of system. As far as operating equipment with remotes, most people won't notice a difference between the two types of pumps.

There are generic hydraulic fluids out there, however they are not all the same grade of fluid. I would look up what Deere calls for on your 4020, probably their Hy-Gard brand fluid. Once you know the specs for the fluid you could cross reference it to a generic type.