Hydraulic Top Cylinder / Float / Cylinder Lock Valve

[MtnViewRanch]

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'm talking a short steep bank that you do not drive on. Makes no difference, I'm just passing on info from my customers. I don't do much mowing at all, so I have no personal experience. My main tractor use is grading and field work.

 

[TheOldHokie]

I'm talking a short steep bank that you do not drive on. Makes no difference, I'm just passing on info from my customers. I don't do much mowing at all, so I have no personal experience. My main tractor use is grading and field work.

What is the functional difference between a hydraulic top link with float and the solid top link with pivoting linkage I pictured? Not much. Both float but the hydraulic cylinder has a greater range of float. Now that extra float might come in handy if I am backing a bush hog up a steep incline but i do that a lot and it would have to be very very steep before the extra float would be needed with my implements.

What is handy is being able to adjust the length of the fixed member on the fly. That way i can increase or decrease the amount of float that pivoting link will allow. I can set it extended for max float and when i lift to transport I can shorten the fixed member to get greater tail wheel lift. Same for backing into a slope. - shorten it to get more float. All I need for that is the normal hydraulically actuated extension/retraction of the rod - not full time float.

Like I said - I will soon have three rear remotes on the tractor. I will also have top and tilt cylinders - perhaps purchased from you I am building my remotes and the cost difference for a 4 way 3 position valve section and a 4 way 4 position valve section with float detent is roughly $40. At that cost differrential I will use the 4 position sections even if I cant come up with an immediate need for it so I will become a member of the top and tilt club.

I am not trying to dissuade anyone who wants a top and tilt kit - by all means go for it and enjoy it to the max. I will be right with you but not sure why at this point. Maybe I will learn something new which always makes the day worthwhile.

Dan

 

[Henro]

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

Float does not cause/affect spool leakage. Some leakage through control valves seems to be normal unless you’re extremely lucky. Over time (with load on it) the length of the cylinder will change, without the control lever being moved.

It’s the check valves that stop leakage from moving through the lines to the cylinder. So the cylinder is effectively locked in place, until you move the control lever and the check valves open.

But check valves and float are mutually exclusive. You can have one or the other, but not both in the same valve section. OR neither. You decide what you want and pay more if you want check valves or float in a valve section.

Just be aware that without check valves your cylinders will likely change in length over time, sometimes at a noticeable rate.

 

[Henro]

Last couple days something seems to have changed when I try to post from my iPad… I tried to edit the above post and ended up with a duplicate that I can not delete…

 

[TheOldHokie]

Float does not cause/affect spool leakage. Some leakage through control valves seems to be normal unless you’re extremely lucky. Over time (with load on it) the length of the cylinder will change, without the control lever being moved.

It’s the check valves that stop leakage from moving through the lines to the cylinder. So the cylinder is effectively locked in place, until you move the control lever and the check valves open.

But check valves and float are mutually exclusive. You can have one or the other, but not both in the same valve section. OR neither. You decide what you want and pay more if you want check valves or float in a valve section.

Just be aware that without check valves your cylinders will likely change in length over time, sometimes at a noticeable rate.

I understand that perfectly.

Dan

 

[ejb11235]

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.

Reviving an old thread

I don't understand this. Why wouldn't connecting the two ports of a cylinder allow the rod to move freely through its entire length of travel? Wouldn't the fluid simply flow from one side of the piston, out the port, into the other port, and into the other side of the piston? What am I missing here?

 

[MtnViewRanch]

Reviving an old thread

I don't understand this. Why wouldn't connecting the two ports of a cylinder allow the rod to move freely through its entire length of travel? Wouldn't the fluid simply flow from one side of the piston, out the port, into the other port, and into the other side of the piston? What am I missing here?

You have to take the rod volume into consideration. Fill a glass full to the rim. Now put your finger in it. You just displaced X amount of volume. So when you have a closed unit, that volume has to go some where. Unless you always fully retract the unit, the rod will always stop at the point where it was when the couplers were-are disconnected.

 

[ejb11235]

You have to take the rod volume into consideration. Fill a glass full to the rim. Now put your finger in it. You just displaced X amount of volume. So when you have a closed unit, that volume has to go some where. Unless you always fully retract the unit, the rod will always stop at the point where it was when the couplers were-are disconnected.

OMG thank you! It took me a while to understand but now I get it. The rod is only on one side of the piston. So when the piston moves, the change in the volume on the rod side is different than the change in volume on the non-rod side. If the cylinder is extending, then you get a vacuum. If the cylinder is retracting, then you get hydraulic lock.

I learned a lot today. Thank you.

 

[ejb11235]

So can you add a "float valve" like this?

NOTE: Picture edited per @TheOldHokie suggestion

 

[TheOldHokie]

So can you add a "float valve" like this?

View attachment 80222 0

Yes but for clarity I would describe that as:

1. Blocks both cylinder ports when pulled out
2. Connects both cylinder ports to tank when pushed in.

Dan

 

[ejb11235]

Yes but for clarity I would describe that as:

1. Blocks both cylinder ports when pulled out
2. Connects both cylinder ports to tank when pushed in.

Dan

Cool. Thanks for the editing suggestion ... the text was copied from the description of the valve on surpluscenter. I have edited and updated the original diagram above. The valve is the Prince SS-2B1D. Looking at the pictures, it appears that the handle can be moved to the opposite end of the spool. That way the operation would be push-in to turn float off, pull to turn float on.

 

[TheOldHokie]

Cool. Thanks for the editing suggestion ... the text was copied from the description of the valve on surpluscenter. I have edited and updated the original diagram above. The valve is the Prince SS-2B1D. Looking at the pictures, it appears that the handle can be moved to the opposite end of the spool. That way the operation would be push-in to turn float off, pull to turn float on.

I have used several of the valves in that family and currently have a three way on my L3901 for my log splitter outlets. Both ends of the spool are drilled and tapped for the knob allowing the valve to be operated from either end. They also have drilled and tapped holes in the casting for panel mounting - see picture below.

Dan

 

[ejb11235]

I have used several of the valves in that family and currently have a three way on my L3901 for my log splitter outlets. Both ends of the spool are drilled and tapped for the knob allowing the valve to be operated from either end. They also have drilled and tapped holes in the casting for panel mounting - see picture below.

Dan

Thanks for the picture! I've never done anything with hydraulics before, so this is pretty fun learning new stuff. I've spent hours looking at valves and specs over the last couple of days and learning the terminology and the options and thinking about my project. I learned how to make the drawings in Visio.

My goal here is to put rear remotes on my BX23S so I can have a hydraulic top and tilt if I decide I want it. A big question is whether I'm going to try to use the Kubota rear remote kit and adapt it, or completely roll my own solution. My plan is to diagram out the as-built, then diagram out what the system would look like using the rear remote kit, and then diagram a completely custom solution. Should be fun, even if I never implement it.

Oh, did you fab up that bracket for the valve? It looks sweet! I love the label.

 

[TheOldHokie]

Thanks for the picture! I've never done anything with hydraulics before, so this is pretty fun learning new stuff. I've spent hours looking at valves and specs over the last couple of days and learning the terminology and the options and thinking about my project. I learned how to make the drawings in Visio.

My goal here is to put rear remotes on my BX23S so I can have a hydraulic top and tilt if I decide I want it. A big question is whether I'm going to try to use the Kubota rear remote kit and adapt it, or completely roll my own solution. My plan is to diagram out the as-built, then diagram out what the system would look like using the rear remote kit, and then diagram a completely custom solution. Should be fun, even if I never implement it.

Oh, did you fab up that bracket for the valve? It looks sweet! I love the label.

Careful - this stuff can get addictive and then you start raiding the kids college fund to pay for shiney new shop tools.

Bracket is just a piece of 11 ga flat bent 90 to fit between the fender and cross stay. Angle grinder, hole saw, and drill press for holes and slots. Label courtesy of MSWORD and Avery heavy duty outdoor adhesive labels.

Dan

 

[ejb11235]

Careful - this stuff can get addictive and then you start raiding the kids college fund to pay for shiney new shop tools.

Bracket is just a piece of 11 ga flat bent 90 to fit between the fender and cross stay. Angle grinder, hole saw, and drill press for holes and slots. Label courtesy of MSWORD and Avery heavy duty outdoor adhesive labels.

Dan

I don't have any kids. Oh wait, I don't have any money either. Oh well.

Avery outdoor labels...these guys? Did you print the black? Since it's color, am I correct in assuming you used an ink-jet printer?

 

[TheOldHokie]

I don't have any kids. Oh wait, I don't have any money either. Oh well.

Avery outdoor labels...these guys? Did you print the black? Since it's color, am I correct in assuming you used an ink-jet printer?

Not those - Avery Heavy Duty ouutdoor lsbels - dont have the number handy. Printed on a color laser and they do fade. The ones you linked look like they might work well.

Dan

 

[ejb11235]

Not those - Avery Heavy Duty ouutdoor lsbels - dont have the number handy. Printed on a color laser and they do fade. The ones you linked look like they might work well.

Dan

sounds more like these https://www.avery.ae/labels/heavy-duty-labels

 

[TheOldHokie]

sounds more like these https://www.avery.ae/labels/heavy-duty-labels

Nope - Avery 6575 but there are lots of products to choose from. I actually bought these for my mailbox....

Dan

 

[ejb11235]

Nope - Avery 6575 but there are lots of products to choose from. I actually bought these for my mailbox....

Dan

Well now that we have that problem solved, I need to think of something outside that needs a label.

 

[Chad D.]

Well, I read most of the tread and seems In hope I’d find an answer to my little dilemma….

I’ve got a Fit Rite top link and my valve has float a detent. It’s solid for the majority of my use, but it does bleed off over some time. My idea to stop this when I want it to remain at a specific point is to simply slap a 1/4 turn ball valve on one of the lines to the cylinder.

Assuming I match the valve to available pressure, is there anything I can screw up? Seems like it’s as safe as keeping the valve open when the cylinder is at full stroke. Can’t go anywhere…

Thoughts?