Understanding rear hydraulic remotes

You may look in the back of the tractor and see a rear hydraulic outlet and assume that they're all the same, and really that couldn't be further from the truth. There's a lot of different styles of valves and how they work mechanically, and a lot of different hydraulic systems that are pumping the oil through these valves. Some of these differences can be really important, depending on the types of implements that you're choosing to put behind your tractor.

So first, in the mechanical sense, there's a lot of different ways that these valves can work. The cheapest and least expensive valve is called a spring center valve, where you'll have a simple lever and when you press it forward or back and let go of it, it pops right back to the center position. Those valves are the most mechanically simplistic, and they're the least expensive.

Spring center valves can often be about half the price of the more deluxe counterparts that you sometimes will see on other tractors. Spring centers don't have any kind of float function or hold-open function, and thus can limit you in certain applications. You can't float a spring center in order to raise your transport wheels, or you can't lock it open for constant flow. 

There's two types of detents that you can have in a rear remote, and the first of those types will be a float detent, where you push the valve forward and you'll feel a pop and it goes over top of a detent ball, and holds the valve in a forward position. Now, when you pop into that detent, you're going into what's known as float, and when you're in the float position, essentially you're just opening this thing up so the oil can freely flow from one side to the next, without any kind of pressure flowing through it from the tractor.

Typically, float valves are usually used in order to do transport wheels. If you have a transport system on a disc or something, you can throw it in the float position so it just drops to the ground allowing the wheels to move freely underneath of it. Guys will often use it to on top and tilt kits. If you want the top cylinder in order to be able to move on its own without any kind of input from the tractor, to say, grate or contour something, afloat detents are a really nice way to do that.

The second way is a self cancelling detent. Now, self canceling detent is going to allow you to take that valve and push over the detent. Once the valve comes to a place that the oil starts to dead end, it will pop that thing back into the neutral position. Again, we can go back to that transport wheels that we were talking about before, if you go into your self canceling position you can raise your wheels up until the the cylinder extends and the valve stops flowing oil, and at that point the valve will jump back to neutral.

Now, that's an important thing to have for certain applications because you don't want that oil to be pushing through bypass or be dead ending in there, because it tends to create a lot of heat and stuff in your hydraulic system, so a self cancelling valve can help in those kinds of applications. Mechanically, that's how your valves work, but there's two different systems that are out there that are actually pumping oil into these valve stacks and that's known as open or closed center.

Open center systems are typically found on most tractors under about 150 horsepower, and you have a simple gear pump that's running a pumping oil, and the oil is going to go out the path of least resistance, so if you start using multiple functions on here at the same time, the oil is going to go out whichever function is the easiest for it to flow out of, and that can cause some unpredictable behaviors when you're doing complex operations.

The alternative to that is a closed center system. Close center pumps are typically variable displacement pumps. They can dial their demand up or down depending on the needs and demands of the rear remotes, and so if you need to have, say, constant flow or a constant pressure out a certain outlet, closed center systems are able to deliver that. They're also usually done with electronic rear remotes, where these things can have a lot of, say, program abilities, to say, run for two seconds and turn off, or have automatic headland functions and really advanced systems, and very demanding and advanced tractors for production agriculture

A lot of interesting systems that you can get into some for some really demanding applications, so if you have questions about your hydraulic systems, you're looking for a tractor, or we can help you with parts or service needs, give us a call at Messick's. We're available at 800 222 3373 or online on messicks.com.