JD 4020 'Farmhand F258 Loader Hydraulic Control Valve Re

texasvinny

New User
Hi All! I purchased a JD 4020 this past year and am in the process of putting it to more active use. It came with an old 'Farmhand F258'
loader. The loader hydraulic control valve appears to be 'two spool' and is not working as effectively as it may have way back when. In
searching for a new loader hydraulic controller to replace it with, I'm faced with options such as 'hydraulic pressure', 'hydraulic flow
rate' & 'hydraulic type'. John Deere says that the 4020's internal hydraulic characteristics are: hydraulic pressure = 2,250 psi, total hydraulic flow = 18 gpm and hydraulic type =
'Closed'.

My question is: Does the new, replacement loader hydraulic control valve characteristics need to be equal to or higher than 2,250 psi & 18
gpm and does this new control valve also need to be 'Closed' so that it matches the characteristics of the JD 4020?

Thanks in advance for any and all constructive guidance!
 
I have a JD 148 loader on my 4020. I went with the MDS Sur-Lock quick attach since I had a pin-on bucket and hay fork.
The bucket pins on my loader are 1 diameter, 32 1/4 between centers, and the brackets were 3 1/2 wide.
I have skid steer mounts on my other big tractor, but the MDS mounts are just as easy to use, and usually a little faster to swap than the skid steer.
 

You need a closed center valve (or one that converts to closed center with the use of a closed center plug). It needs to have a flow rating equal to or greater than the tractor's flow rating. Most of the convertible valves can allow adjusting their main relief valve up to 3000 PSI (+/-). On a closed center system, you will need to adjust that relief valve to the maximum pressure (so it is inoperable, as the closed center system has its own relief). If your current loader valve has a detented float position, you will need to check the specs on the valves you look at. Some valves advertised for loaders do not have a float position for the lift spool.
 
Thanks, Jim! Understand regarding the closed center, flow rating and pressure. The term 'detent' has me scratching my head, though. With
my current loader control (single 'joystick'), I can push the lever forward a bit and the loader moves downward until I stop pushing the
lever. When I stop pushing the lever, the loader stays at the new position and the lever returns to 'neutral' position. Same process
happens when I move the lever to one side or another (e.g. the bucket tilts down or up, accordingly and the lever returns to 'neutral'
position). Does everything I've just described mean I have a detented float position? Thanks!
 
I've just watched a video on float/ detent and have answered my own question. I do not currently have float or a detent position in my
current valve and joystick setup, since, I can push as hard as I want and the lever will not stay in the pushed position (e.g. detent).
And, once I let go, the loader and/or bucket will not move further (hence, no float, either). If I've got this correctly, now, I'd
appreciate a 'you got it right' from you, just to be sure! Thanks!
 
(quoted from post at 19:09:00 05/23/23) Thanks, Jim! Understand regarding the closed center, flow rating and pressure. The term 'detent' has me scratching my head, though. With
my current loader control (single 'joystick'), I can push the lever forward a bit and the loader moves downward until I stop pushing the
lever. When I stop pushing the lever, the loader stays at the new position and the lever returns to 'neutral' position. Same process
happens when I move the lever to one side or another (e.g. the bucket tilts down or up, accordingly and the lever returns to 'neutral'
position). Does everything I've just described mean I have a detented float position? Thanks!

The float would be only on the lift spool. Can you push the lever forward passed the point where the arms are lowering? It might take a hard push, to make it snap into the detent, and it will stay in that forward (lowering) position even if you let go of the lever. You would need to pull back on the lever to free it from the detent, so it can spring return to center. That forward position, if it locks there, is the detented float position and the bucket will drop to the ground, basically by gravity. When the bucket reaches the ground when you are lowering the arms by holding the lever (if you have double acting cylinders) you could lift the front of the tractor, if you hold the lever in the lowering position. If it will go passed that point and lock forward, the lift cylinders are open to the reservoir on both sides allowing the lift arms to float up and down, which in turn allows the bucket to follow the ground as you move.
 

It sounds like you got it. A picture of the caps on the ends of your valve spools, opposite end from the lever ends, should confirm that. If both caps are the same length, likely no float. If the lift spool has a longer cap it may have float detent that is not working.
 

cvphoto155199.jpg

These are the opposite ends and, like you shared, they are the same length. No float or detent.
 

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