Control valve?

[TSMART]

Koyker 160. (2004) Bucket uncurls completely within 60 seconds. Within the same 60 seconds the main loader lowers from all the way up to halfway where it stops and stays there. Main hydraulic cylinder rebuilt a month ago; no problems till this started. No visible leaks. No air in lines. Control valve?? Or is this related to the rebuilt cylinder? Hydraulic fluid is full. Need advise thanks. Control valves pricey.

 

[piper184]

Some questions:
Are you saying that while the bucket is uncurling (dumping) the loader also lowers to midpoint un-commanded (no up or down movement at the joystick)?
Can you raise and lower the loader completely without rolling the bucket?
Were both lift cylinders rebuilt?
Are you able to raise the front end of the tractor with the loader?
Can you hear anything that sounds like a pressure relief valve opening (like the sound it makes when a cylinder hits end of travel)?

You could swap the hoses at the control valve so that the "up/down" movement controls the bucket tilt and the "left/right" movement controls the loader lift. Awkward to use but would be useful indicator if the problem stays with the lift cylinders or if it stays with the control valve movements.

 

[Bob Rooks]

I'll add to Piper's post:
Do you have a regen detent in your valve that lets you dump the bucket quickly, or a float position for the lift arms?
When you say "main hydraulic cylinder" what do you mean? There are two bucket cylinders, and two lift cylinders

 

[TSMART]

Some questions:
Are you saying that while the bucket is uncurling (dumping) the loader also lowers to midpoint un-commanded (no up or down movement at the joystick)?
Can you raise and lower the loader completely without rolling the bucket?
Were both lift cylinders rebuilt?
Are you able to raise the front end of the tractor with the loader?
Can you hear anything that sounds like a pressure relief valve opening (like the sound it makes when a cylinder hits end of travel)?

You could swap the hoses at the control valve so that the "up/down" movement controls the bucket tilt and the "left/right" movement controls the loader lift. Awkward to use but would be useful indicator if the problem stays with the lift cylinders or if it stays with the control valve movements.

I can lift the bucket all the way up but itll come down to halfway then stop. Within a minute. I can completely curl in the bucket but soon as I'm off the stick itll totally uncurl in a minute. One lift cylinder was rebuilt a month ago. I have not tried to lift front end with the bucket. Will do so first thing tomorrow.

 

[TSMART]

I'll add to Piper's post:
Do you have a regen detent in your valve that lets you dump the bucket quickly, or a float position for the lift arms?
When you say "main hydraulic cylinder" what do you mean? There are two bucket cylinders, and two lift cylinders

Lift cylinder rebuilt a month ago. I can float the bucket.

 

[Bob Rooks]

I can float the bucket.

You should not be able to float the bucket, but you should be able to float the lift arms if circuits are plumbed correctly. So you do not have a regen circuit? Does it make any difference if the engine is running?
It sounds to me like a hydraulic lock is being created, but goes away when the joystick is moved.

 

[Unclewillie]

Koyker 160. (2004) Bucket uncurls completely within 60 seconds. Within the same 60 seconds the main loader lowers from all the way up to halfway where it stops and stays there. Main hydraulic cylinder rebuilt a month ago; no problems till this started. No visible leaks. No air in lines. Control valve?? Or is this related to the rebuilt cylinder? Hydraulic fluid is full. Need advise thanks. Control valves pricey.

let the pressure off and check quick connects for small amounts of water. Just small amounts of moisture / water can cause that.

 

[piper184]

What you are describing is a leak down issue. The bucket leaks down all the way but the loader arms only leak down halfway.

The two things that can cause this that I know of are internal cylinder leakage (from one side of the piston to the other) or an internal leak in the control valve where fluid is leaking past a part that is supposed to be blocking it.

Unless fluid is leaking out of the quick connects, I can not see how they could be involved at all, water or not. Most hydraulic fluids contain emulsifiers that hold water in suspension of the fluid so that it will not pool up in the bottom of the tank or freeze solid. If you have water in the fluid it will most likely have a milky appearance to it.
That raises the question of what fluid are you using?
Also, why was the one cylinder rebuilt and what was done to it?
If you raise the loader all the way up and push the joystick into "float" how does it behave? Does it come down gently or slam like it has been dropped?
Did this issue start immediately after re-installing the repaired cylinder or did it work fine for a while before this started happening?
Does it leak down at the same rate with the engine off as it does with the engine running? (not sure why this would matter but it might be a clue)

 

[TSMART]

What you are describing is a leak down issue. The bucket leaks down all the way but the loader arms only leak down halfway.

The two things that can cause this that I know of are internal cylinder leakage (from one side of the piston to the other) or an internal leak in the control valve where fluid is leaking past a part that is supposed to be blocking it.

Unless fluid is leaking out of the quick connects, I can not see how they could be involved at all, water or not. Most hydraulic fluids contain emulsifiers that hold water in suspension of the fluid so that it will not pool up in the bottom of the tank or freeze solid. If you have water in the fluid it will most likely have a milky appearance to it.
That raises the question of what fluid are you using?
Also, why was the one cylinder rebuilt and what was done to it?
If you raise the loader all the way up and push the joystick into "float" how does it behave? Does it come down gently or slam like it has been dropped?
Did this issue start immediately after re-installing the repaired cylinder or did it work fine for a while before this started happening?
Does it leak down at the same rate with the engine off as it does with the engine running? (not sure why this would matter but it might be a clue)

Ok. I have a few more clues. Can I lift front of tractor off ground? Yes, but only for a second. When I drop the lift from way up, yes it comes down very quickly. Another clue: my boot on control arm broken for years. Since tractor was kept dry I figured no problem. But now you have me thinking I might have moisture in there. I know that in front of the seat there is a stack which controls speed of drop. Wondering if I should adjust or tighten. None of this affects the 3 point. It works fine. Thank you again for your assistance.

 

[TSMART]

The cylinder was rebuilt because it was leaking badly. Using hydraulic fluid. It has a spin on hydraulic filter.

 

[Bob Rooks]

Does it leak down at the same rate with the engine off as it does with the engine running? (not sure why this would matter but it might be a clue)

With the engine running there is a constant supply of oil to the control valve (this is an open center system) and you would not be able to detect any leak-back from a bad or maladjusted spool. Since answering my question about regen has been ignored, I'll just assume that function is not present in the control valve.
Onward.

 

[TSMART]

The truth is I dont know what regen means. Thanks for trying to help me.

 

[TSMART]

The truth is I dont know what regen means. Thanks for trying to help me.

My control valve only 2 axis. Up down dump retract.

 

[piper184]

The knob under the seat only controls how fast the 3 point lowers. The 3 point is a single acting cylinder that is powered after the loader and after the power steering. The pressure relief valve for the steering and 3 point is in the 2 point control valve. Your loader control valve may or may not have it's own pressure relief valve.

I don't know the capacity of your loader but it is probably 600# plus. Can your loader lift a load that is close to it's capacity?

It is beginning to sound like a control valve issue. To properly troubleshoot we would need to know make and model of the valve itself.There may be internal adjustments that can be made.

Personally I would do the hose swap test first to try and isolate the problem further. Then perhaps take the control valve apart and see if there is anything obvious. Since this started sudenly, you might find a broken spring or cracked housing or something. Having a parts manual for the valve would be very helpful.

 

[Bob Rooks]

My control valve only 2 axis. Up down dump retract.

To simplify: Regen is short for regenerate. It would be a position beyond a detent in your "dump" position. You would have to exert a little extra force to overcome it (you may have it and not know it). What it does basically is to open the circuit between the ram piston sides, thus creating a loop so the oil passes freely form one side of the piston to the other. The bucket will literally fall open because there is no return to the reservoir through the valve.

I used this valve when I re-plumbed my tractor loader. It has float, regen, and power beyond features.

Amazon.com: Brand Hydraulic Loader Directional Control Valve LV22RFSTKAB Joystick

Amazon.com: Brand Hydraulic Loader Directional Control Valve LV22RFSTKAB Joystick

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[TSMART]

Update. Had my tractor mech drop by. He was concerned about the pump as I had to add one gallon fluid to top off. Bucket hoses are like cement. Very super hard and brittle..no flexibility at all. They are original equip 2004. He felt that most likely a piece of rubber broke off inside the hose and went to the control valve. So now I'm looking at control valve or rebuild kit for Koyker 160 loader. For now I chained the bucket in place so I could at least use box blade. My two mains lift the bucket but very slowly even at cruise rpms. Hope to hell that's it and not the pump too.

 

[TSMART]

So today I changed hydraulic filter. No help. Shortly after I was using the box blade. Discovered a huge leak in my other main lift cylinder. ( opposite side rebuilt a month ago. Can an internal leak turn into an external leak and do you think that cyl is going to be the root of my problem. Also, on the Koyker 160 does $400 sound about right for repack/rebuild. Thanks.

 

[Bob Rooks]

So today I changed hydraulic filter. No help. Shortly after I was using the box blade. Discovered a huge leak in my other main lift cylinder. ( opposite side rebuilt a month ago. Can an internal leak turn into an external leak and do you think that cyl is going to be the root of my problem. Also, on the Koyker 160 does $400 sound about right for repack/rebuild. Thanks.

I think $400 is a little steep for re-sealing one cylinder. They aren't that big, and hopefully you'll get the urethane cup seals.
An internal leak will not cause an external leak unless there is extreme over-pressure - likely you'll blow a hose first.
If you have a compound joystick with debris in it, it could be the cause of your problems (you may have some or none of these functions). Some regular joystick valves will work with the red arrows also.

 

[Kyle87]

These guys may be a good source for your koyker needs. I bought a valve from them to convert my zl20 loader and had a very good experience.

Short Line Parts Short Line Parts Home Page Parts for Koyker Front End Loaders - Joystick Kits

Purchase short line parts online: Koyker cylinders, Koyker rebuild kits, complete plumbing packages, attachments, and joystick parts.

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