Hydraulic Top Cylinder / Float / Cylinder Lock Valve

[MidwestMike]

Not sure if this should be in Implement section, but considering the valve and cylinder is involved...

I am not clear on something for the top cylinders, locking valves and float.

I see people installing rear remotes with floats, but then ordering the Surplus Center top links with the lock valve. To me this seems like a contradiction.
> How does a float valve work with a locking cylinder?


I also notice that Fit Right does not use a lock-valve cylinder.
Which leads to another question. I understand what the lock valve does, but if it is required,
> how come my loader cylinders carry a heavy bucket fine without a lock valve?

(For "simplicity" I went with electric valves for the rear, same setup as front joystick type. I realized I would loose float but did not realize at the time time the importance. Was figuring to use chain when required, but realize now how useful it would be. (Could still add it with another diverter...)

 

[Henro]

Not sure if this should be in Implement section, but considering the valve and cylinder is involved...

I am not clear on something for the top cylinders, locking valves and float.

I see people installing rear remotes with floats, but then ordering the Surplus Center top links with the lock valve. To me this seems like a contradiction.
> How does a float valve work with a locking cylinder?
View attachment 61973

I also notice that Fit Right does not use a lock-valve cylinder.
Which leads to another question. I understand what the lock valve does, but if it is required,
> how come my loader cylinders carry a heavy bucket fine without a lock valve?

(For "simplicity" I went with electric valves for the rear, same setup as front joystick type. I realized I would loose float but did not realize at the time time the importance. Was figuring to use chain when required, but realize now how useful it would be. (Could still add it with another diverter...)

Float in a control valve will have no use if paired up with a cylinder that has a check valve assembly built into it.

My control valves for rear remotes all have built in pilot operated check valves, except for the one section that has the float function. The options were one or the other, not both, because float and check valves are not compatible.

Hope this makes sense...and helps somewhat...

 

[MtnViewRanch]

The DPOCV (locking check valve) is required in Europe? Most of the off the shelf cylinders that you find for sale with the check valves are built in Europe.

As you have come to realize, there are several advantages for using the float feature on top & tilt cylinders, thus Fit Rite does not provide the check valves unless asked.

The main reason for them here in the states IMO is simply to eliminate the issues caused by poor quality rear remote valves. Pretty much all valves used for rear remotes on these utility tractors small and large alike leak some. There is without a doubt better quality valves than others. Unfortunately for whatever reason Kubota seems to use the best loader valves of the different tractor manufactuers, but the worst rear remote valves.

My feeling is as long as the valve does not leak bad enough to hinder operation, then it is fine. Some people think that the cylinder should not move at all and that is simply unrealistic to expect that kind of performance and still have the float feature benefit.

Many, even most people are fine with not having the benefits of the float feature, and that is fine.
I personally would not be without it. A lot of this comes from making use of the benefits of using the float feature for the various tasks that benefit from using that feature.

 

[MidwestMike]

The DPOCV (locking check valve) is required in Europe? Most of the off the shelf cylinders that you find for sale with the check valves are built in Europe.

As you have come to realize, there are several advantages for using the float feature on top & tilt cylinders, thus Fit Rite does not provide the check valves unless asked.

The main reason for them here in the states IMO is simply to eliminate the issues caused by poor quality rear remote valves. Pretty much all valves used for rear remotes on these utility tractors small and large alike leak some. There is without a doubt better quality valves than others. Unfortunately for whatever reason Kubota seems to use the best loader valves of the different tractor manufactuers, but the worst rear remote valves.

My feeling is as long as the valve does not leak bad enough to hinder operation, then it is fine. Some people think that the cylinder should not move at all and that is simply unrealistic to expect that kind of performance and still have the float feature benefit.

Many, even most people are fine with not having the benefits of the float feature, and that is fine.
I personally would not be without it. A lot of this comes from making use of the benefits of using the float feature for the various tasks that benefit from using that feature.

Thanks for the response, and it does line up with what I'm thinking. (Wish I would have thought more before going all electric to be "simple". Adding a diverter now to get float back sure goes beyond simple )

 

[farvebret]

Would like to get a Hydraulic top link cylinder for my L4701. Have the remote valves on the tractor. L8560, L8562A and L8303

Looking for recommendations a company to contact

 

[MtnViewRanch]

Thanks for the response, and it does line up with what I'm thinking. (Wish I would have thought more before going all electric to be "simple". Adding a diverter now to get float back sure goes beyond simple )

A separate electric valve that allows the cylinder to be in float mode can be added for about $100 plus switch & hose costs. I've done this before on an LS tractor that does not offer a float feature for their rear remotes.

 

[MidwestMike]

A separate electric valve that allows the cylinder to be in float mode can be added for about $100 plus switch & hose costs. I've done this before on an LS tractor that does not offer a float feature for their rear remotes.

I should have built it in to the plan, but I figured a cheap diverter valve between the cylinder ports would do it for me if needed. About half as much for a manual setup. (Would serve me right to have to reach for it after not planning it out.. )
Glad to hear it's been done, I'm not totally nuts thinking about it...

Interesting it was on LS. Every LS I've ever seen on the lot had the dual rears. (did not know missing float). It sure would be cheap for Kubota to make them standard, if they weren't worried about taking this nice markup from the dealer...

 

[MtnViewRanch]

I should have built it in to the plan, but I figured a cheap diverter valve between the cylinder ports would do it for me if needed. About half as much for a manual setup. (Would serve me right to have to reach for it after not planning it out.. )
Glad to hear it's been done, I'm not totally nuts thinking about it...

Keep in mind, it is not just connecting the 2 ports to each other, but those ports need to connect to a tank port also.

 

[MidwestMike]

Keep in mind, it is not just connecting the 2 ports to each other, but those ports need to connect to a tank port also.

I was thinking a diverter between the two cylinder ports, and the other leg going back to flow from the valve. Normal would have cylinder port 1 connected to valve. Flipping would cut out the valve and have cylinder ports 1 and 2 connected. I'm thinking with 1 and 2 connected the cylinder would float.

I don't have tank port, which is one of the reasons of using the electric manifold instead of electric sub plate. It works the same a forward third function kit that does not need a tank connection.

Does that sound right..? Thanks.

 

[MtnViewRanch]

I was thinking a diverter between the two cylinder ports, and the other leg going back to flow from the valve. Normal would have cylinder port 1 connected to valve. Flipping would cut out the valve and have cylinder ports 1 and 2 connected. I'm thinking with 1 and 2 connected the cylinder would float.

I don't have tank port, which is one of the reasons of using the electric manifold instead of electric sub plate. It works the same a forward third function kit that does not need a tank connection.

Does that sound right..? Thanks.

The only way that would work properly would be to fully retract the rod before you put it in float mode.
If in any other position, the rod will only retract to the position that you opened the valve. If the rod was fully extended and you opened the valve, nothing would move at all.

You really need to find a return to tank port if you were to do this and have full movement at any point of operation.

 

[MidwestMike]

The only way that would work properly would be to fully retract the rod before you put it in float mode.
If in any other position, the rod will only retract to the position that you opened the valve. If the rod was fully extended and you opened the valve, nothing would move at all.

You really need to find a return to tank port if you were to do this and have full movement at any point of operation.

Thanks for the info. I was only working by theory, and it appears my theory was wrong.

I was thinking the cylinder would float when both ports were connected, and could then break the float when that leg connected back to the valve.

 

[TheOldHokie]

Thanks for the info. I was only working by theory, and it appears my theory was wrong.

I was thinking the cylinder would float when both ports were connected, and could then break the float when that leg connected back to the valve.

Float position on a directional control valve connects both ports to tank. See valve schematic.

Dan

 

[GeoHorn]

…
As you have come to realize, there are several advantages for using the float feature on top & tilt cylinders, thus Fit Rite does not provide the check valves unless asked.
…

Can you expand on that?

My most common rear implement is a finish mower… next by a rotary-shredder—-next by a blade—- or a PHD.
The hydraulic top-link replaces a factory, threaded/adjustable, …but “fixed position” top-link….which Never “floats”. (If a “float” were needed one would simply put the 3-pt ctrl in the lowest position …or not use a top-link.)
When I use a finish mower…it rolls on its’ own 4 casters and the top link has no need to “float” because the 3-pt has been lowered to its’ lowest setting thereby allowing the mower to roll on its’ own wheels/casters. Same thing with a blade.

A PHD never needs to “float” hydraulically.…. So, it makes me curious why a hydraulic top-link replacement for a factory, mechanically “fixed” top-link somehow has a greater need to “float”.
Thx.

 

[TheOldHokie]

Can you expand on that?

My most common rear implement is a finish mower… next by a rotary-shredder—-next by a blade—- or a PHD.
The hydraulic top-link replaces a factory, threaded/adjustable, …but “fixed position” top-link….which Never “floats”. (If a “float” were needed one would simply put the 3-pt ctrl in the lowest position …or not use a top-link.)
When I use a finish mower…it rolls on its’ own 4 casters and the top link has no need to “float” because the 3-pt has been lowered to its’ lowest setting thereby allowing the mower to roll on its’ own wheels/casters. Same thing with a blade.

A PHD never needs to “float” hydraulically.…. So, it makes me curious why a hydraulic top-link replacement for a factory, mechanically “fixed” top-link somehow has a greater need to “float”.
Thx.

I tend to agree but with a slightly different perspective. My mower and shredder both use the fixed top link but float on their own linkage.

Dan

 

[GeoHorn]

I tend to agree but with a slightly different perspective. My mower and shredder both use the fixed top link but float on their own linkage.

Dan

Exactly!

 

[MtnViewRanch]

Ever mow pond banks? I have many customers that state that even though their mowers have the floating linkage, it does not allow the mower to move enough for their conditions-circumstances. This would also apply for backing up a bank and mowing the lower part of the bank.

Plus, not everyone has the floating linkage on their mowers.

It's great that you guys don't need that feature for your purposes.
Everyone does not have the same situation.

 

[TheOldHokie]

Ever mow pond banks? I have many customers that state that even though their mowers have the floating linkage, it does not allow the mower to move enough for their conditions-circumstances. This would also apply for backing up a bank and mowing the lower part of the bank.

Plus, not everyone has the floating linkage on their mowers.

It's great that you guys don't need that feature for your purposes.
Everyone does not have the same situation.

Ever mow pond banks? I have many customers that state that even though their mowers have the floating linkage, it does not allow the mower to move enough for their conditions-circumstances. This would also apply for backing up a bank and mowing the lower part of the bank.

Plus, not everyone has the floating linkage on their mowers.

It's great that you guys don't need that feature for your purposes.
Everyone does not have the same situation.

I mow plenty of banks - my property is on big bank and i have been mowing it for 35 years with a solid top link. I can see the value of float on a tilt cylinder but top link not so much. I am in the process of engineering remotes for my new L3901 and right now it looks like its going to be two with float and one wirh 2 position detent. Cant find a use for more than one with float but the difference in cost is small so why not.

Dan

 

[Henro]

I mow plenty of banks - my property is on big bank and i have been mowing it for 35 years with a solid top link. I can see the value of float on a tilt cylinder but top link not so much. I am in the process of engineering remotes for my new L3901 and right now it looks like its going to be two with float and one wirh 2 position detent. Cant find a use for more than one with float but the difference in cost is small so why not.

Dan

I think the “why not” is because valve sections with float suffer from leak down, where sections with pilot operated check valves lock the cylinders in place and it takes a very long time before it becomes noticeable. My assumption, as I have never noticed cylinder length change with cylinders connected to valve sections with check valves built in.

I put put four rear remotes on my B2910 probably 16 years ago. Have not needed more than three, and that’s because I have two tilt cylinders. I love having one remote with float, no question about that!

That being said, with two tilt cylinders I can see a possible convenience when plowing snow on compound curves...but one works reasonably well if I put the other cylinder at mid point.

 

[TheOldHokie]

I think the “why not” is because valve sections with float suffer from leak down, where sections with pilot operated check valves lock the cylinders in place and it takes a very long time before it becomes noticeable. My assumption, as I have never noticed cylinder length change with cylinders connected to valve sections with check valves built in.

I put put four rear remotes on my B2910 probably 16 years ago. Have not needed more than three, and that’s because I have two tilt cylinders. I love having one remote with float, no question about that!

That being said, with two tilt cylinders I can see a possible convenience when plowing snow on compound curves...but one works reasonably well if I put the other cylinder at mid point.

Why does float affect spool leakage? I am currently looking at using valve sections from a vendor that like most provides empirical spool leakage data:

Spool leakage measured @100Bar., with 27cSt@40C oil viscosity, and operating temperature of 50C:

12 cc/min max, 6cc/min average

That applies to ALL spool types including spools with a fourth float position. Number of positions does not change the leakage rate.

Dan

 

[NCL4701]

Example of use for top link float.

Bush hogging sewer line which is crossed by several ditches (two with rip rap), terraced water breaks, and have to cross two creeks to get there. Bush hog has single rear wheel and hitch has a slot for top link that allows “float” of about 2”. Crossing creeks requires raise lift and crank top link all the way in to avoid binding. Terraces and ditches require flexing both toward and away from tractor; top link off. Rip rap ditches require lifting to carry the mower over the ditch while cutting saplings, etc. well above the rocks. Top link back on.

So if I was mowing just fields it likely wouldn’t be an advantage to float. Or I could continue to connect and disconnect the top link as needed; hydraulic or not. Don’t mow the sewer line more than once or twice a year so that wouldn’t be awful. Or I could use the turn buckle top link to get some exercise and spend more time outside. Or I could make the top link go from up to down to float by moving a small lever by my right hip without leaving the seat, which requires a float detent valve for a top link without check valves.

So far as other 3 point stuff, that would be box / back blade, chipper, generator. The chipper and generator obviously sit on the ground during use, just need the top link for transport so set, lock, and forget isn’t needed. For blade work… Maybe some applications setting the top link in the morning and having it dead locked without moving the rest of the day or week is important. For the road maintenance, trail maintenance, and ditch maintenance I’m doing it isn’t. Don’t need it flopping all over the place but extreme precision over long times simply isn’t necessary. I suppose if I run across something where I need the top link locked down like a vise over some lengthy time I could take the hydraulic top link off and revert to the turn buckle temporarily. I currently swap the grapple for bucket or forks routinely and sometimes remove the whole loader so removing a quick connected top link shouldn’t be some deal breaking PITA. Don’t know why I’d ever remove it but also don’t know why I wouldn’t if it’s a problem for some specific task I don’t currently have.

Edit: I would say for draft work such as plowing or discing with a 3 point implement a slightly leaky top link wouldn’t be great. But: 1) I don’t do that; 2) I suspect the R4’s would be more of a problem than the top link;
3) Drawbar type plows and discs do exist and the rear hydraulics would work just swell to run them.