Hydraulic Adapter Plates

I currently have a 600 with a loader and 3pt backhoe. The loader is tapped into the backhoe's hydraulic system. I'm planning to sell this
tractor without the backhoe and need to re-route the loader's hydraulics. I know the loader will be slower using the tractor hydraulics, but
that's what I'm going with because I'm not spending the money on a front pump setup. Can someone tell me which adapter plate is the better
setup: HV4902 or HV5902. I'm a little confused by some of the comments I've found on other sites. Thanks.

4902 has pressure and return, 5902 also has power beyond port,which you need depends how your hydraulics were done.

Understand, and that's the issue. I have to rework the hydraulics to the loader. I don't understand the pros/con's of either setup.

If there are only two lines going to and from the loader control valve in addition to the lines going to and from the loader cylinders, then you don't need the power beyond plate. If there are 3 then you do, or you need to convert the control valve so that it's open center without power beyond.

2 lines = open center
3 lines = open center + power beyond

Currently it is a two line connection with the loader in series (and before) the backhoe. Line one comes out of backhoe pto pump to the loader control valve. Line two comes out of loader control valve and into backhoe pressure input.

So, to make sure I understand correctly. I should be able to use the 4902 with one line leaving pressure output of 4902 valve to input of loader control valve. Then line two leaves loader control valve to return of 4902 valve. And, this set up will allow both the loader and 3pt to function?

(quoted from post at 15:41:33 02/01/17) Currently it is a two line connection with the loader in series (and before) the backhoe. Line one comes out of backhoe pto pump to the loader control valve. Line two comes out of loader control valve and into backhoe pressure input.

So, to make sure I understand correctly. I should be able to use the 4902 with one line leaving pressure output of 4902 valve to input of loader control valve. Then line two leaves loader control valve to return of 4902 valve. And, this set up will allow both the loader and 3pt to function?

Click to expand...

Yes, that is correct.

I won't confuse you with any details on why it is incorrect to put two open center control valves in series without a power beyond port, but suffice to say that the configuration with the loader and backhoe was not optimal, but it makes it easier for you to remove the backhoe.

Please, if you have time - try to explain. Or, can you point me in the direction of a good web site to learn more about it. Not sure if it
is related to the incorrect setup or lack of power, but it does feel like the hydraulics bog the tractor down when starting out from a dead
stop. This is the Amazon product title for the cheap valve I put on the loader: NorTrac Monoblock Hydraulic Control Valve - 12 GPM, 2 Spool

(quoted from post at 18:43:49 02/01/17) Please, if you have time - try to explain. Or, can you point me in the direction of a good web site to learn more about it. Not sure if it
is related to the incorrect setup or lack of power, but it does feel like the hydraulics bog the tractor down when starting out from a dead
stop. This is the Amazon product title for the cheap valve I put on the loader: NorTrac Monoblock Hydraulic Control Valve - 12 GPM, 2 Spool

Click to expand...

The usage of two open center control valves in series without a power beyond configuration should have nothing to do with the tractor bogging down when starting out from a dead stop unless there is some restriction to the flow when the valves are centered and has nothing to do with what I was referring to.

A plain open center control valve is designed to dump the fluid back to the sump via the return port and having a second control valve downstream can result in unexpected back pressure on the first valve if you are trying to use both control valves at the same time. A power beyond setup is designed to deliver power to the downstream control valve while still providing another return port that has no back pressure so the unpowered side of the cylinders can evacuate the fluid back to the sump.

Let's take your loader and backhoe configuration as an example:

When you are operating the loader by itself and not touching the backhoe controls, as you raise or lower the arms or curl or dump the bucket, one side of the cylinders is getting pressure and fluid flows into them, while the the fluid in the other side of the cylinders is evacuating and dumping back to the sump.

When you are operating both control valves at the same time is when the back pressure occurs.

Let's say you are trying to set the tractor up to dig with the hoe, so you lower the backhoe stabilizers at the same time that you are lowering the loader arms so that the loader bucket and the stabilizers are all pushing down into the ground to stabilize the tractor, but if the backhoe stabilizers hit the ground first, the back pressure from the pressurized side of them will make it more difficult for the loader arms to lower because the side of the cylinders on the loader that are trying to evacuate the fluid has back pressure and so they wont' evacuate as easily.