Top-Link - how to get the benefits of both DPCV and Float?

PandDLong · Dec 7, 2012

I recently received my new Kubota L3540 and, based on all the great info on TBN, I ordered a hydraulic top-link and rear remotes with float. Unfortunately, I didn't do enough reading - and my dealer didn't pose any questions or offer advice - so I wasn't anymore specific in my order than just that.

What I received is a hydraulic top-link with DPCV and (after some rework with the dealer) a valve with float. Now that I've read every thread about DPCV, I believe that this is a useless combination.

However, after reading all those threads I'm pretty sure that sometimes I will want DPCV features and sometimes I will want float. Since I have both in my possession - is there any way to be able to use the feature I want when I want it? i.e Is there a way to "turn-off" the DPCV when I want to float?

Or is this an impossible ask and I really need to pick one or the other? Or buy another top-link and swap them based on my needs at the time?

I love hydraulics when they work, but it can a tangled web of information and optins for an amateur...

MtnViewRanch · Dec 7, 2012

It is not realistic to be able to use both. While it could be done, it would be bulky and costly. The sad thing is that you did not get a Kubota top link when you ordered from a Kubota dealer.

Although it is my understanding that Kubota only sells complete "TnT" kits for the L series at this time.

How I look at it is being able to have & use the float function far outweighs the positive locking that the DPOCV gets you. If your control valve leaks down bad enough that the amount of drift affects your grading, then the valve needs to be rebuilt or replaced. If you are farming, then use the manual adjusted link. People ask me about this all the time. I get asked if my valves leak, yes they do. They leak down at a rate of just under 3/16" per hour and that is with a 1000lb implement hanging on the hitch up in the air. That is 30 thousandths of an inch every 10 minutes and when you are grading, it is very seldom that you will go more than that between adjustments. I'm not sure about everyone else, but 30 thousandths is plenty close enough for me.

Just my :2cents:

murphy1244 · Dec 7, 2012

Mtn View, I just had the other remote added to my Kioti and the service guy it won't do float. What can I do to make it float?

EE_Bota · Dec 7, 2012

In my experience, float can't work with cross port checks, but float can make cross-port checks work.

Almost always in industrial hydraulics, if there are cross port checks, they are meant to be the most leak proof member of the circuit, but to make sure the checks close, pressure needs to be relieved from both pilots. So regardless of whether the system is open or closed center, A and B are sent to T to make sure the pilots are relieved and the checks do close. Your float position can send A and B to T, overcoming at least that problem even if the actual checks do preclude the possibility of actual float action.

MtnViewRanch · Dec 7, 2012

murphy1244 said:
Mtn View, I just had the other remote added to my Kioti and the service guy it won't do float. What can I do to make it float?

Unfortunately I am not really familiar with the OEM remote :ashamed: other than I know that Kioti does indeed have a remote valve for the DK series that does have the float function with it.
So you are sure that the lever only has 3 positions? It will not go past the up-down position? Did you order the 2nd valve with the float function? If the Dealer was aware that you wanted the float function, it seems like that is what you should be getting? If not, well, it may cost you to get it switched out.

I am very sorry that I can't really help you out.

/pine · Dec 7, 2012

I'm curious and my ignorance on the topic got the best of me...

What 3PH attachments make it desirable to have the top link float?
When I added three (with room for a 4th) rear remotes I made sure one has a float detent for certain implements but I can't think of any reason I would want the htl to float

TIA

MtnViewRanch · Dec 7, 2012

/pine said:
I'm curious and my ignorance on the topic got the best of me...

What 3PH attachments make it desirable to have the top link float?
When I added three (with room for a 4th) rear remotes I made sure one has a float detent for certain implements but I can't think of any reason I would want the htl to float
TIA

Using a mower. You set the tail wheel and set the 3pt at the desired height. You can then mow some pretty rough up & down ground and the mower will follow the terrain. There are times when even a floating link that some mowers have is not enough. The other option to use float is the side link of a Top & Tilt setup. This is great for doing finish grading-smoothing on a road at a Y or T intersection where the camber of the road changes. The implement will just follow the grade instead of what the tractor is doing. Another place to use the float function with the side link is when you are raking an open area that is rough. All you want to do is clean it up, not level it out.

Just a few examples.

murphy1244 · Dec 7, 2012

Also when hooking up a implement you can grab the top and push or pull to connect.

/pine · Dec 7, 2012

MtnViewRanch said:
Using a mower. You set the tail wheel and set the 3pt at the desired height. You can then mow some pretty rough up & down ground and the mower will follow the terrain. There are times when even a floating link that some mowers have is not enough. The other option to use float is the side link of a Top & Tilt setup. This is great for doing finish grading-smoothing on a road at a Y or T intersection where the camber of the road changes. The implement will just follow the grade instead of what the tractor is doing. Another place to use the float function with the side link is when you are raking an open area that is rough. All you want to do is clean it up, not level it out.

Just a few examples.

Thanks...it makes perfect sense...since I've never pulled a mower, brush hog etc...it never dawned on me...seems the same would apply to a landscape rake with wheels attached...?

As far as the side link goes...I've said before...you were oh so right that the (hydraulic) side link is paramount when it comes to perfecting grade work... just like you've said...I am constantly adjusting the side pitch with box blade, scrape blade and the rake...I am now going to check out using the float on the HSL...may have to add some weight to the rake and bb to make them a little more spontaneous...(given the flow restrictions etc.) Thanks again:thumbsup: and as soon as I add the 4th rear remote it will definitely have a float (detent) function...!

Also when hooking up a implement you can grab the top and push or pull to connect.

Considering the CV for my HTL is within hands reach this has not been an issue for me but I see your point...

MtnViewRanch · Dec 7, 2012

/pine said:
Thanks...it makes perfect sense...since I've never pulled a mower, brush hog etc...it never dawned on me...seems the same would apply to a landscape rake with wheels attached...?

Yes, same thing applies to any implement with gauge wheels.

bumperm · Jul 11, 2014

Old thread, but, if one has a DPCV top cylinder and needs a float function, would it not be possible to install a manual bypass between the cylinder's ports with a shut off valve between them? For normal operation the bypass is closed and the pilot check valves lock up the cylinder to eliminate creep. For float operation with tractor running, or to lower an implement or manually position the top cylinder with the tractor off, the bypass valve is manually opened.

bumper

kennyd · Jul 11, 2014

bumperm said:
Old thread, but, if one has a DPCV top cylinder and needs a float function, would it not be possible to install a manual bypass between the cylinder's ports with a shut off valve between them? For normal operation the bypass is closed and the pilot check valves lock up the cylinder to eliminate creep. For float operation with tractor running, or to lower an implement or manually position the top cylinder with the tractor off, the bypass valve is manually opened.

bumper

Possible, yes. But the fittings, lines and valve will need to rated for pressures at or above 3000psi-no Home Cheapot parts here from the plumbing isle.

bumperm · Jul 11, 2014

kennyd said:
Possible, yes. But the fittings, lines and valve will need to rated for pressures at or above 3000psi-no Home Cheapot parts here from the plumbing isle.

Agreed. Got most of the stuff to do my top and tilt, both cylinders with DPCV, from SurplusCenter. I did have to modify tilt cylinder, cutting off fittings and welding on new at appropriate angles to fit lift links.

Tilt shown does not have DPCV . . . I installed that later to eliminate creep.

I don't have float on either cylinder, but did add chain to my field mower, so at least for now have no need for float - - can always leave top link disconnected if need be.

bumper

jenkinsph · Jul 12, 2014

I have not seen the need for check valves in my work and while I do have float for the top link I seldom use it. If my valves leaked enough to notice I would fix them.

MtnViewRanch · Jul 12, 2014

jenkinsph said:
I have not seen the need for check valves in my work and while I do have float for the top link I seldom use it. If my valves leaked enough to notice I would fix them.

People that mow a lot with a rotary cutter in rough terrain make use of the float function with the top link. People that smooth things out in general, not trying to have a flat grade use float with the side link.

I have never used float mode with my top link. I don't mow with a rotary cutter. I use float mode with my side link at the 6 different intersections just about every time when I am finish smoothing the 1+ mile drive that I maintain .

Good control valves = zero need for DPOCVs. :thumbsup:

jenkinsph · Jul 12, 2014

Brian,
My side link can be set to float or be fixed on the connection to the hitch arm. I use it loose for most things including grading. Just yesterday building up a low spot I used this to keep the box blade level as the tractor pitched 15 degrees or better as I drove off the pile. Must have about 2 inches of play in a slot below the lift cylinder if that makes sense.

Sold my MX6 cutter, didn't really need it and was concerned about all the gear box problems that might happen. At any rate this cutter had the float built into it.

MtnViewRanch · Jul 12, 2014

With the slots that John Deere has, you get to be able to allow the implement to move up on each side independently.

John Deere recommends the use of those slots when using a 3pt mower and a roto-tiller. Obviously there are many other tasks that they serve well.

Several of the other makes have slots in the clevis of the side link also, typically only on their larger tractors though. JD has them on the 3000 series and up. :thumbsup:

jenkinsph · Jul 12, 2014

I would have thought all of them have the free play but haven't really looked to verify this.

Fallon · Jul 14, 2014

I love float on my top link when mowing. I've taken to mostly leaving it in float. Then retracting it a hair to back over ditches & holes. Leaves the tail wheel just off the ground so it doesn't fall in. Gives overall better control than just lifting with the 3pt.

Haven't found a use for the sideline in mowing yet. Float there just means 1 side of the cutter gouged things up as it sags.

MtnViewRanch · Jul 14, 2014

Fallon said:
I love float on my top link when mowing. I've taken to mostly leaving it in float. Then retracting it a hair to back over ditches & holes. Leaves the tail wheel just off the ground so it doesn't fall in. Gives overall better control than just lifting with the 3pt.

Haven't found a use for the sideline in mowing yet. Float there just means 1 side of the cutter gouged things up as it sags.

Float with the side link would never be used with a 3pt rough cut (bush hog)mower. Only for a finish mower that has wheels at all corners.