I .have a jinma 254 when I try to raise the 3 point it goes down slowly and won't raise I can lift it manualy and it will stay in place. Any Ideas. I was skidding a heavy log when it started
I'm guessing you raised the lift lever to the max to get the nose of the log outa the dirt. Happens a lot with post-hole diggers too, trying to raise the auger those last few inches outa the hole. Those thumbscrew stops are there to prevent what likely just happened. The upper lift arms were permitted to travel too high, which caused the lift piston to extend outside the cylinder. That takes the piston O-ring and wiper(s) outide the cylinder. When you lower the lift, the piston pulls back inside the cylinder - damaging the the seals and wiper(s) as they're pulled back inside the cylinder walls.
It's a common occurrence with inexperienced Jinma 200 Series owners, and one they seldom repeat. It's an inexpensive fix, but is time consuming and messy. Hence most owners learn by their first mistake. It's such a common problem, that most Jinma dealers carry the "repair kit" in stock at all times.
Thanks Greg, If the seal and wiper are out will it settle.
I have a winch mounted on the skid plate and used it to pull the 3pt up and it stays up even with a heavy load. I would have guessed something else because I would have thought it would settle with a bad seal. What are your thoughts?
I'm sorry, I don't understand what you just wrote. As far as lifting/settling, an initially damaged seal/wiper will lift - then settle. As the damage gets worse, lifting capacity decreases - settling occurs faster.
Alternatively - but much less common - you could have a problem with the lift valve itself. And loads that stay up (won't drop at all) - that can be caused by the flow control valve (front of seat, between legs) being either closed or clogged.
If I jack the 3 point up manualy and hold it there with a jack, then pull the up lever for a few seconds I can see it is trying to lift but doesn't have enough flow to lift it on its own. If I then remove the jack it will stay there without settling. There is clearly flow going to the cylinder trying to lift it but there isn't enough pressure to lift it. Is there anyway the fluid could be bypassing in the valve? not allowing enough pressure to lift. as soon as you try to lift with the 3 point up it will fall to the ground. almost as fast as if you were trying to lower it
Well, I still suspect the O-ring and wiper. But yes, there's a pressure relief valve inside the hydraulic sump. But ordinarily you'd hear the engine RPMs drop leading up to that thing opening up. I'm not sure what you're accomplishing by jacking up the lift arms. Under normal circumstances, you should be able to do that by hand. The rate of fall when you let go is then controlled by the position of the flow control valve in front of the seat.
For a hands-on diagnosis, you might want to take the tractor over to Ryan Delaney in Oconomowoc. His contact info is below.
I called the dealer I bought it from and they were sure it the relief valve they said no way is it the cylinder seals.
If it were the 3point wouldn't stay up. For the record the relif valve is not in the sump but thanks anyway for your help.
O by the way I jacked ut up because the attachment was still hanging on there and I had to get it back to the barn. I suppose I could have dropped it in the woods but didn't want it sitting outside.
I called the dealer I bought it from and they were sure it the relief valve they said no way is it the cylinder seals.If it were the 3point wouldn't stay up. For the record the relif valve is not in the sump but thanks anyway for your help.Dan
I'm not in a position to question the competence of your dealer. But that's a pretty absolute statement. When the piston O-ring and wiper suffer minor initial damage, they in fact will lift - but suffer leakdown relative to the position of the flow control valve. Over time the seal damage progresses, as does the lifting capacity and the speed of the leakdown.
That said, some of the detritus from the damaged seals could have coincidentally clogged up the relief valve.
I worked on the tractor last night. I took the pressure relief valve apart, cleaned it and reassembled it. It must not have reset properly. Everything works fine now. problem solved. Thanks for you help.
3 point problems: Chinese Tractors -- Jinma/Farmpro/ Agracat -- Chinese Tractors Discussion Forum
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