How do you use your Top-Link: Fixed, Float or Adjustable

[MtnViewRanch]

Basically a double-pilot check valve keeps a hydraulic cylinder from contracting or expanding. When used on top and side link hydraulic cylinders one can position an implement one time and it will remain at the initial settings, just link the fixed manual top and side links. Hydraulic cylinders used in a top-and-tilt system without the double-pilot-check valve will drift and change while in use requiring constant or frequent adjustments. The red hydraulic cylinder in the picture on this haytools.com web page is equipped with a double-pilot-check valve.Hydraulic top links, Top-N-Tilt, hyd. Side link cylinders

May I ask what you consider constant or frequent adjustments? :confused3: My side links on my tractors drift at a rate of less than 3/16" per hour and that is with all the weight of the implement up in the air for testing purposes. I'm sure on the ground it is less. I have NEVER that I can think of had to compensate for any drift with my top links.

I have said this many times, if you have a drifting problem, then most likely your control valves need to be either rebuilt or replaced. Nothing wrong with having the DPOCV, just that IF you have the float function with your valves, then you are missing out on several different working options that can be used with the hydraulic links.

 

[94BULLITT]

May I ask what you consider constant or frequent adjustments? :confused3: My side links on my tractors drift at a rate of less than 3/16" per hour and that is with all the weight of the implement up in the air for testing purposes. I'm sure on the ground it is less. I have NEVER that I can think of had to compensate for any drift with my top links.

I have said this many times, if you have a drifting problem, then most likely your control valves need to be either rebuilt or replaced. Nothing wrong with having the DPOCV, just that IF you have the float function with your valves, then you are missing out on several different working options that can be used with the hydraulic links.

When you say they drift 3/16" were are you taking that measurement? The implement, lift arm, or the cylinder itself?

 

[MtnViewRanch]

I guess because none of the ones I've used has ever had float on the rear outlets, nor have I seen one on any other machine (or even heard of one). Must not be a popular option here?

Well, either it is not a popular option as you have said of there are people that have it and do not know it. I have many customers that have been the later and are happy customers when they realize that they do indeed have the float function. :cool2:

 

[Gator6x4]

May I ask what you consider constant or frequent adjustments? :confused3: My side links on my tractors drift at a rate of less than 3/16" per hour and that is with all the weight of the implement up in the air for testing purposes. I'm sure on the ground it is less. I have NEVER that I can think of had to compensate for any drift with my top links.

I have said this many times, if you have a drifting problem, then most likely your control valves need to be either rebuilt or replaced. Nothing wrong with having the DPOCV, just that IF you have the float function with your valves, then you are missing out on several different working options that can be used with the hydraulic links.

Control valves are expensive. How do I know? I purchased two of them because I was told with a straight face, your control valves are leaking causing the constant drift or leak down of implements. Then I was told, try these with pilot valves and if the problem isn't corrected I will buy new control valves and replace them. Needless to say no more purchasing of control valves have occurred.

Several have posted on this forum and other forums about the top and side link leaking down or changing when using tillers, box blades, scrape blades, etc. By the way I have the little used, like new Gannon hydraulic cylinders lying under a work beach in the shop if you are interested in buying. Sold with the understanding if used in a top and tilt setup leak down and drift will occur.

 

[MtnViewRanch]

Control valves are expensive. How do I know? I purchased two of them because I was told with a straight face, your control valves are leaking causing the constant drift or leak down of implements. Then I was told, try these with pilot valves and if the problem isn't corrected I will buy new control valves and replace them. Needless to say no more purchasing of control valves have occurred.

Several have posted on this forum and other forums about the top and side link leaking down or changing when using tillers, box blades, scrape blades, etc. By the way I have the little used, like new Gannon hydraulic cylinders lying under a work beach in the shop if you are interested in buying. Sold with the understanding if used in a top and tilt setup leak down and drift will occur.

I don't want to argue with you, I can only say what has been my own personal experience with my own cylinders and my customers. I have had 2 complaints about leak down-drift, I told my customers what I would do to take care of it, one person with a Kubota L5740 swapped control valves with the top link and side link and has had no problems since. Another customer had a problem and I recommended a solution and he never got back to me, did it take care of the problem, I don't know. Usually no news is good news, but I just don't know.

You did not answer my question either about how often is frequent? As far as your control valves, I guess that the new ones didn't take care of the problem? I have had to rebuild some Prince valves, std o-rings that come in them didn't take care of the problem and they leaked pretty much from the time that they were new. Put in lip seals instead of the std o-rings and problem was solved. Lip seals were less than 25 cents a piece.

Again, nothing wrong with the links with the DPOCV, you just lose the options that are available if-when a person has the float function available to them. You don't see those options as being valuable and that is fine, no big deal. There are a lot of people that do make good use of the float option.

 

[MtnViewRanch]

When you say they drift 3/16" were are you taking that measurement? The implement, lift arm, or the cylinder itself?

Great question, that is at the cylinder itself. I just went out and checked it to see what it was at the cutting edge of the box blade itself and it was 9/16". So 9/16" drift in 60 minutes comes out to be just over 1/8" every 15 minutes. If you are using the top and tilt for grading which is what they are mainly used for, not really that big of a deal. Is it perfect? No, but very real world and to have the ability to float the implement when desired is well worth it to me and apparently many others.

Have you found that your Kubota "TnT" links drift much?

 

[94BULLITT]

Great question, that is at the cylinder itself. I just went out and checked it to see what it was at the cutting edge of the box blade itself and it was 9/16". So 9/16" drift in 60 minutes comes out to be just over 1/8" every 15 minutes. If you are using the top and tilt for grading which is what they are mainly used for, not really that big of a deal. Is it perfect? No, but very real world and to have the ability to float the implement when desired is well worth it to me and apparently many others.

Have you found that your Kubota "TnT" links drift much?

Someone was having trouble with their sidelink drifting with their 1000# rotary cutter on. I put my rotary cutter on which is probably 500#'s and measured the drift on mine with a caliper. Started out by measuring at the implement but I thought the toplink may drift and effect the sidelink measurement. I measured with the caliper on the sidelink for about 45min one night here are the results.

time measurement
9:27 1.128
9:46 15 9/16 1.169
10:12 15 1/2 1.193

I don't notice any drfit. I am always making adjustments if a blade or the pallet forks is on the 3PH.

 

[MtnViewRanch]

Someone was having trouble with their sidelink drifting with their 1000# rotary cutter on. I put my rotary cutter on which is probably 500#'s and measured the drift on mine with a caliper. Started out by measuring at the implement but I thought the toplink may drift and effect the sidelink measurement. I measured with the caliper on the sidelink for about 45min one night here are the results.

time measurement
9:27 1.128
9:46 15 9/16 1.169
10:12 15 1/2 1.193

I don't notice any drfit. I am always making adjustments if a blade or the pallet forks is on the 3PH.

Exactly, a person is always making adjustments. That's why we get hydraulic links. So we are back to, do the none check valve links move, YES. Do they move enough that it really makes any difference, no. Most of the time if they do drift excessively, then there are usually other problems that should be addressed.

 

[94BULLITT]

Exactly, a person is always making adjustments. That's why we get hydraulic links. So we are back to, do the none check valve links move, YES. Do they move enough that it really makes any difference, no. Most of the time if they do drift excessively, then there are usually other problems that should be addressed.

I forgot to say that those measurements where in inches.

 

[npalen]

A restrictor fitting plumbed into either of the cylinder ports can allow controlled cylinder float. These fittings will typically look identical on the outside but are plugged with a small orifice drilled thru the plug. A hole diameter of 1/32" to 1/16" might be considered as "middle of the road" on a larger cylinder such as 4" bore. Smaller bore cylinders used on top and tilt applications might require even smaller diameters. The restrictor slows down the action of a cylinder whether the valve is being used in directional mode or float mode. It would not act the same as, for example, a chain being used as the top link as the speed of the cylinder is controlled. Another way of controlling cylinder speed is by hose inside diameter. I'm surprised that 1/4" hoses are not used with top and tilt cylinders as the flow volume would be plenty fast in most applications. Some may perhaps feel that the smaller diameter hoses are not rugged enough although a double wire braid hose will take a lot of abuse.
As an aside to the orifice diameters mentioned above, it should be realized that doubling the diameter of an orifice will nearly quadruple the flow at a given PSI. (Think pie are squared) Also, while true that restrictor orifices generate heat, it should not be a factor with only infrequent adjustment of the TNT cylinders required.