Parker/Gresen 400 Control Valve

Farmall dean · Oct 7, 2016

Farmall Super A 1950 with loader. The Gresen 400 (4 way 3 position)moves the bucket up and down (double acting). When the lever is pulled toward the operator the bucket pivots up. The problem-when the lever is pulled SLOWLY back the bucket pivots DOWN and will not pivot up until the lever is pulled full back. In many cases this is not a big problem but it is easy to unintentionally dump the load, which is dangerous, can injure someone or drop the new refrigerator when unloading from the truck.
A new Parker/Gresen 400 is almost $400. Anyone know of a fix? Maybe find a used one?
Dean in Joseph, Oregon

David G · Oct 7, 2016

I have seen this on valves with float position and the adjustment screws have come loose.

Farmall dean · Oct 7, 2016

I don't believe this valve has a float position adjustment screw but will check it.
Thanks

Hayfarmer · Oct 7, 2016

I am not sure about the 400 valve. I had that issue with my JD loader some years back. Bought a new valve with internal check valves. works fine now.

pete 23 · Oct 7, 2016

Has it always worked this way. Does it make a difference if you run the engine at higher rpm's. That valve does not have a reverse flow check valve. (check valve that won't allow oil to flow back toward pump before pump can over come the loaded bucket). There are a couple ways to check this out but it may be easier to take the spool out to see if anything has partially unscrewed. With nothing in the bucket, if you pull the lever slightly, enough for bucket to start tilting, will it recover while holding the lever in that same position and then reverse the tilt. If it does, you have a reverse flow problem and you could install a check valve in the inlet to the valve allowing flow to only go into and not out of valve. If not, I personally would remove valve and do testing with air pressure to find which way things are flowing. Air pressure is your friend when trouble shooting hydraulics.

Farmall dean · Oct 7, 2016

I removed the spindle and it looked fine to me I am not a hydraulic expert). The rubber O rings looked ok, maybe a little hard. No scoring or dirt. This valve has always been "sticky" compared to the 300 next to it. If I recall correctly, I have to help center the spindle when I push it to full travel. It wants to "stick".It does not float freely as does the 300. There is only one thing that can unscrew and that is the screw that holds the spring and it was very tight.
I can't run a test as you suggest as the spool is out. But I don't recall the bucket recovering if I hold the spool in the same position. I have to pull it further back to reverse the tilt.
Removing the valve may be the answer and testing with air.
I am going to take the spindle to the shop that works on all the heavy equipment in the area Monday and see if they can find anything obvious.
Could the o rings (2) be old and stiff and make the valve "sticky" so it does not properly center?

Parker/Gresen 400 Control Valve

Farmall dean

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David G

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Farmall dean

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Hayfarmer

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pete 23

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Farmall dean

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