Chatter Hyd. Top Link

[BlacknTan]

I've read so much here about the hydro top links and how the ones with the DPOCV are preferable to those without..
Am I reading correctly that the DPOCV now be a cause of a chatter like this?

Now I might have to re-think things...

 

[jinman]

The negative pull on the cylinder causes the check valve to close, the hydraulics catch up with pressure and opens the valve and the cycle repeats. It recycles quickly making the chatter.

Now that is an interesting theory. We don't know Jim's tractor type, amount of hydraulic flow, or plumbing. If there is air in the line or air pockets, it sure could cause havoc with a DPOCV. On my tractor, I have installed 0.030" orifices to reduce flow and let me have nice slow control of my toplink. I have never experienced any chatter due to low flow, but I can sure see where air or bubbles in the oil might cause a DPOCV to go nuts.

 

[Jim Ronquest]

Dang, I did not mean to start such a discussion. I was just looking for other possible causes. Although the pins do not seem tight without a load on the QH, once there is an attachment hanging on there it would certainly increase the pressure on the pins, and could very well be squawking, as Jinman said, I hate to grease them as that would attract lots of dirt.

The Top Link does have check valves. Someone else also mentioned to me about using 1/4 inch Hyd. Lines rather than 3/8. Also when you start either to extend or retract the cylinder, it is asking more from the pump and will load or pull down the engine a fair amount especially if you are trying to feather the attachment. Once the valve is fully open or shut RPMs will return. It would be great for the top link to operate as smoothly as say the FEL however it does its job and sure beats not having one.

The tractor is a Case IH DX 40 with almost 100 hours.

Thanks again for all of the feedback.

JimBo

 

[Redneck in training]

Now that is an interesting theory. We don't know Jim's tractor type, amount of hydraulic flow, or plumbing. If there is air in the line or air pockets, it sure could cause havoc with a DPOCV. On my tractor, I have installed 0.030" orifices to reduce flow and let me have nice slow control of my toplink. I have never experienced any chatter due to low flow, but I can sure see where air or bubbles in the oil might cause a DPOCV to go nuts.

I second that. Since the bubble is compressible it could change pressure in the cylinder depending on load and cause the CV chatter. Stroke the link full stroke several times at different angles of the cylinder so the air can exit from the cylinder. Depending on the length of the lines between the valve and the cylinder it could require greater or smaller number of strokes to get the bubble to the valve and oil return.

 

[jinman]

Dang, I did not mean to start such a discussion.

So many of us have a hydraulic toplink that this is gonna bring a lot of discussion, especially from those of us with a DPOCV.

You and I have the same hydraulic system. When you operate our remotes, the open center system starts to close off so that pressure is generated and available as soon as the remote valve opens. That's the engine loading you hear. Our loader's joystick is more complex and has an internal checkvalve to stop the loader from dropping before pressure is applied. The joystick doesn't have the preload that the remote does.

I have a CCM toplink with 1/4" hoses and a 0.030 orifice. My toplink has never chattered, but it does squawk as I've mentioned before. With our systems capable of 9 gpm, there is no loss of pressure. I think air in the hydraulic system is unlikely after you cycle the toplink all the way out and back in a few times.

 

[Jim Ronquest]

Thanks again, I understand where you are coming from on the discussion deal.

I, at one time thought it was air also, but after a good bit of cycling and daily use a couple hours in the evenings and some weekend time any air should of been worked out by now.

It appears I should at least try some 1/4 inch lines and go from there.

Thanks again,

JimBo

 

[radman1]

The chattering double piloted check valve I mentioned earlier was an added on check valve. Was not designed and integrated into the cylinder like some. My dealer warned me that they had issues like that before I tried it. I had the chatter. It should be noted that I used the check valve on a Toolcat curl/bucket which has a single larger cylinder than a Top link cylinder. I use added on check valves on my top link cylinder and on my tilt cylinder of my Toolcat 3pt and do not have any chatter. I suggested that as a possibility. The check valve that had the chatter was a new Vicker's valve. I have not tried it on any other cylinders. Unsure of why I had the chatter on the curl cylinder. Could be related to higher flow in the larger curl cylinder? The weight of the bucket is certainly less than the weight of 3 pt implements that I use.

 

[Redneck in training]

Thanks again, I understand where you are coming from on the discussion deal.

I, at one time thought it was air also, but after a good bit of cycling and daily use a couple hours in the evenings and some weekend time any air should of been worked out by now.

It appears I should at least try some 1/4 inch lines and go from there.

Thanks again,

JimBo

I still think that there is air. Disconnect the top link and cycle it standing up and hanging down as well. 1/4" lines could help due to their lower volume. If the lines are long and their volume is greater than volume of the cylinder it is difficult to expel all air trough the valve to oil return.

 

[Jim Ronquest]

Thanks again for all the help.

In the process of elimination I lightly greased all of the pins to try and see if that might help and I also cycled repeatedly at different angles. I was able to alleviate some of the chatter some of the time. By just barely opening the valve and extending as slow as I possibly could, the cylinder would extend fully chatter free with the Box Blade. Other times it would start immediately, yet other times would start at approximately 50% extension. It is still more apparent with the heavier attachments, although can be quite noticeable with the LRake.

Would it be worth switching the hyd. lines to 1/4 inch? Or just deal with it. As it does not seem to be hurting anything.

Thanks again.

JimBo

 

[Redneck in training]

Yes. Depending on their length. Smaller lines have lower volume so it is easier to pass the possible air bubble via the valves to the oil return. The bubble might stay in the larger hoses and come back to the cylinder. If the cause of the chatter is air you will get rid of it regardless of houses diameter but it might take some time.