Link arms stuck up. 1963 NP super major.

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JGLea
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Link arms stuck up. 1963 NP super major.

Post by JGLea »

Hi all, I’m a bit stuck. My hydraulic link arms will raise fully but will not go back down. I’ve had the cylinder off and that is not seized. None of the linkages are seized. The only thing I didn’t check is if the main control valve is stuck thinking about it now. Is this common?

When I remove the external services block it allows oil to flow out and the arms to lower. Could there be something stuck shut in there not allowing oil to return? Or is it just a case of that main control valve being stuck below the main lift cylinder? Or something else blindingly obvious or very common that I’m not clued in on.

Many thanks chaps and chapettes

Josh

Billy26F5
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Re: Link arms stuck up. 1963 NP super major.

Post by Billy26F5 »

Is the drop control knob in the fully shut position? If so the arms will be very slow to lower. Try attaching a plough or something similar and try then. If they still don't come down then the adjustments might be out.
Sandy
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JGLea
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Re: Link arms stuck up. 1963 NP super major.

Post by JGLea »

Hi sandy, link arms do not lower at all. They don’t creep down or anything when left for a long period. But they are free! I assume this is the knob closest to the steering wheel? I noticed the small shuttle it pushes with the O ring was tough to move however when I reassembled the top cover I ensured this was at the fully out position to check it wasn’t this. If you’re referring to the flow control, this was removed for a tipping pipe. I did notice that when the PTO was running the draft control clevis wouldn’t move even with a very large bar on it. When the PTO was off it would move easily with a bar. Maybe this is a sign of the problem. Alternatively could something be stuck in the auxiliary control plate?

Emiel
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Re: Link arms stuck up. 1963 NP super major.

Post by Emiel »

Hi,

Just an answer from memory. Not checked it in the manual, but can’t it be a sticky unload valve?

Rgds emiel.
Best regards

Emiel

N 1937, E27N 1948, 8N 1949, E27N 1950, E1A Diesel 1953, E1ADKN PP 1956, Dexta 1959, NH Clayson M103 1964

JGLea
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Re: Link arms stuck up. 1963 NP super major.

Post by JGLea »

Hi, all I know is that oil is free to return if the auxiliary services block is removed. I removed it and pushed the link arms down and oil came out which would suggest that the cylinder is being told it can return however the oil cannot take a pathway to return thus holding pressure in the fully up position? As I say I believe it’s either the main control valve or something stuck in the auxiliary services block. But not 100% and don’t want to rip them apart if it’s not either of those. That’s why I’m trying to get a couple of opinions first. Thanks all

Billy26F5
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Re: Link arms stuck up. 1963 NP super major.

Post by Billy26F5 »

It's not the unloading valve for lowering. Try putting a plough on and see how quickly it comes down. If it still doesn't come down, try cleaning the return filter and check the back pressure valve there too.
Sandy
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AdrianNPMajor
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Re: Link arms stuck up. 1963 NP super major.

Post by AdrianNPMajor »

You ask if something is stuck.
The answer is yes.
Please give us some history on the tractor. Have you just acquired it? My guess is yes.
KR, Adrian.

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