FEL up and down very slow on Jinma 454

Doesn’t sound like a pump or flow problem if the other parts are working normally.

Does it sound like the relief valve is opening? The same sound as it makes when the cylinder hits the end of its travel?

Since it takes more force to lift the loader than to roll the bucket do you know if the bucket or 3 point still have normal power? Will the FEL lift the front of the tractor off the ground?

If so, I would suspect a plugged control valve or perhaps a hose that is collapsed internally. Rare, but it can happen.

You could swap the lift cylinder hoses at the valve and maybe figure out if the problem follows the lift or lower side of the circuit. IF that doesn’t tell you anything, you could swap the bucket and lift cylinder hoses at the valve. If the problem stays with the lift cylinders, it would indicate the hose/cylinder and vindicate the valve. However if the bucket starts rolling slowly, it would indicate the valve has a problem.

Let us know what you find.

What make and model tractor? Is it a factory loader or aftermarket?

Is this a recent development, or has it always been this way?

How many hours on the tractor?

What was the last thing you did with the tractor before this happened?

CalMiller wrote:

It has not always been this way. It started last fall and I am just getting back to it. i have about 500 hours on the tractor. To be honest I don’t remember the last thing I did before it started raising very slowly. I will try a few of the things Piper mentioned and report back.

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Also, the questions that Tinbender asked are as important.

Are you still using the Chinese quick connects on the loader? If so replace them. There is also a screen under the frame, a little ways behind the pump, follow the suction line. Does the knob under the seat have anything to do with the loader? I have a 454 from Rural King, been a good tractor, have about 100 hrs on it now. That breaks down to abt 10 hours a year. Guess I didn’t need it as much as I thought!

Sounds like either one or both of the lift cylinders are leaking by internally or something going on with the valve, I would bet on its one of the cylinders,if its a Jinma ZL-40 loader we should have rebuild kits for the cylinders, we also stock Koyker rebuild kits from 1-3/4″-2-1/2″ give us a call 979-865-4002
Tommy
Affordable Tractor Sales
“Your Jinma Parts Superstore”
http://www.affordabletractorsalesco.com

Good info. By swapping the hoses and having the problem move to the tilt cylinders, you have eliminated the hoses and the cylinders. This also vindicates the quick couplers, although I would have thought that if they were the problem, all cylinders in the loader would be having the same problem at the same time.

As for what is wrong in the control valve, I suspect you will have to open it up to see. I don’t know about your valve, but the factory one on my 284 was less than desirable and I opted to replace it with the one from Ranch Hand Supply. This allowed me to get a float position and to add future functions using a power beyond port. The increased sensitivity and fine control over loader movements was well worth the investment.

You might consider going this route before tearing into your existing valve. I never opened up my old one as it did function and it now sits in the shop as a backup guarantee that nothing will ever happen to my good valve. Just a talisman to ward off the “Murphy” evil spirit.  😉

Maybe someone who has taken one of these valves apart will be able to help with that.

If you can find a exploded view of the valve that would help a lot, and just be careful when taking it apart, I think it almost has to be trash restricting the flow of fluid.

I had that problem with a ZL-20 a few years back. At the opposite end from the joystick are there two caps on the valve that look like thimbles? If so take those off and you will find a spring under each one with a screw in the center holding them on, the offending control will have a loose screw. Tighten them up and your problem should go away.

That is fantastic! A simple fix that only costs a little time is the best fix.

Thank you for posting the solution. You may never know how many others it will help.

:yahoo:

CalMiller wrote:

So I removed the thimble caps and sure enough it was exactly as Tinbender stated. One of the screws holding the springs was loose. I tightened it down and it works perfectly when re-assembled. All is well. Thanks so much to everyone for your assistance in debugging this hydraulic problem. It is much appreciated. I am still planning to swap out the quick couplers.

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A shining star example of a great member. The follow-ups are greatly appreciated, unlike some members that can’t afford the time.

With all the time and head scratching it took me to figure that out on mine I’m just glad I was able to share what I learned :good:

Just looked at the date this was posted; if you tightened it to much you probably know by now what i write here; You probably have done it well but just make sure that you do not crank down the spring too tight. I assume what you are tightening is the hyd pressure bypass. If the bypass is not working properly every time you extend or retract the cylinder fully, the pressure in your whole system will spike and generally the first thing to go is a hydraulic hose. I have replaced many of my hoses because I had exactly the same problem and tightened the bypass a bit to tight. As you probably know hoses are a pain in the ass to replace as hydraulic shops don’t have this thread, they (or the best one i found anyhow) have one close which works, but definitely is not correct.

No, I didn’t touch the bypass valve, that’s up on top by itself. These screws hold the return springs for the up/down and dump/curl shafts to return to center. They are either screwed down tight and things are working correctly, or they have loosened, and the two shafts your joystick controls cannot return to center. I’ll try to remember to take a picture in the AM.

Here’s a picture of the ZL20 valve. The Green arrow is the bypass valve. If you were to take that apart to clean you would want to mark it and preferably put a gauge inline and write down the pressure reading as well as how many turns it took to take apart.

The Yellow arrows are where the springs live that loosen up causing the up/down or lift/curl valves to not return to center. These screws Must be tight.