Hydraulics

Ford900 · Nov 21, 2014

Hello

On my ford 960 when ever I go to raise the 3 point hitch at idle
it jerks as it goes up, it doesn't go up smoothly. I only noticed
this when it hit cold so would it be just a cold oil problem. It still
goes up fine if the engine is running harder

chrisinsoky · Nov 22, 2014

My 3000 used to do that till i changed the oil. when was the last time yours was changed? another thing as the tractor is warm then cooled it will condensate in there, as it gets cold that little bit of water will freeze. as the tractor warms up does the problem go away?

Ford900 · Nov 22, 2014

I haven't changed the oil in the year I've had it but have added some so that could be the problem. The problem is still there a little after the tractor warms up but not bad

WayneIA · Nov 22, 2014

Your jerking action at the lift arms is because one or more of the six piston in the hydraulic [pump is not pumping oil. This is usually caused by air in the pump. Loosen the 3/8 plug in the front top of the pump,start engine and see if that helps, or take the plug clear out and turn the engine with the starter, with out the engine running, or the best way is to get a 3/8 hose the will reach from the pump plug to the hydraulic fill plug and run until the air is gone.

Ford900 · Nov 22, 2014

But the jerking goes away if you throttle up

Keith Williams · Nov 22, 2014

WayneIA and Ford900,
I also had a pump that showed pulsing at low RPM. In my case, one of the springs that held a check valve against the seat was busted (a cone shaped spring). I believe it was causing a feedback in the circuit.
I rebuilt the pump and it is much stronger now with no pulsing.
HTH
Keith

WayneIA · Nov 22, 2014

If you are sure of no air, than it is pump repair time, or at least pump clean up time. Something under a check valve, broken check valve spring"s" If the pump is completely normal the lift arms are as smooth as silk on the way up.

Ford900 · Nov 22, 2014

Ok thank you, I was just wondering because it started doing this when it got really cold out side

Kurt-NEPA · Nov 22, 2014

A jerky hydraulic system is almost always a suction side air leak. It gets worse with thicker oil in cold weather. I would not discount a piston/check valve spring problem, but I don't think that is your problem.

You can try a pump rebuild kit that includes the check valve springs and balls. Its not too hard to put one the pump. If it works - declare victory. If not, plan on replacing the wobble shaft, bearings, and oil seal. We can help with that if you need it.

In either case, if I pulled a pump for work, I would put a spring rebuild kit on it. So it hurts nothing to try that first.

Hydraulics

Ford900

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chrisinsoky

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Ford900

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WayneIA

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Ford900

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Keith Williams

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WayneIA

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Ford900

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Kurt-NEPA

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