3720 hydraulic toplink

[greg_g]

I have new cat 1 hydraulic top links that go from 19"-29". 2" bore with 1 1/4" rod or 2 1/2" bore with 1 1/2" rod. Center line of pin is 2" off of the hydraulic.

Interesting. Don't believe I've run across a 10" cylinder on a Cat 1 HTL yet. Could you send details via PM or email please?

//greg//

 

[eepete]

Stupid questions: When you guys talk about the length, are you measuring from the center of the holes in the eyes on each end?

I've got a check valve HTL and am thinking of also getting a "normal" one I can float for my JD 4520.

Pete

 

[greg_g]

Yes. Open and closed, retracted or extended, in or out, however you want to express it; we're talking the distance between pin holes.

But now I've got what might be a stupid question; what do you mean by "float"? Toplinks float mechanically on their swivel balls, not hydraulically with their cylinders. Your check valves don't have anything to do with floating. Matter of fact, that design is really oriented toward tractors that have otherwise leaky hydraulic systems. If you had a leaky control valve that would otherwise let your cylinder leak down, the check valves will prevent the leakdown. They just compensate for problems elsewhere in the tractor hydraulic system. If you've got a good healthy hydraulic system, you don't really need one of those check valve cylinders.

//greg//

 

[MtnViewRanch]

Yes. Open and closed, retracted or extended, in or out, however you want to express it; we're talking the distance between pin holes.

But now I've got what might be a stupid question; what do you mean by "float"? Toplinks float mechanically on their swivel balls, not hydraulically with their cylinders. Your check valves don't have anything to do with floating. Matter of fact, that design is really oriented toward tractors that have otherwise leaky hydraulic systems. If you had a leaky control valve that would otherwise let your cylinder leak down, the check valves will prevent the leakdown. They just compensate for problems elsewhere in the tractor hydraulic system. If you've got a good healthy hydraulic system, you don't really need one of those check valve cylinders.

//greg//

Greg, I think that he wants his top link to be able to float as in you put your control lever in the float position. Can't do that when you have check valves. :laughing:

 

[eepete]

The check valves are nice when using the boxblade when I might be on and off the tractor or when then HTL gets bumped a lot. As I understand it, check valves are good for safety if a hose pops, good if valves leak a bit, better at holding their position and they also help cushion the hydraulic system from jolts from the cylinder back into the system (?) I wasn't thinking about float when I got the check valve HTL. Sometimes the learning curve is a bit pricy...

When I have the MX6 or the landplane, the ability to float would be nice. When I cut the safety overflow spillway for a dam, and when I cut a steep hill I have to watch the HTL lenght on the mower. With the landplane, it could truly float over the land like it was being dragged. I do use the HTL with the landplane to adjust the amount of bite, but there are times that a full drag would be useful.

Finally, I suspect my operating skill level is not good enough that I will be able to tell a big difference between float and no float, but it would be interesting to see what the difference is.

Tnx for clarification on the measurement points for HTL and cylinders.

Pete

 

[greg_g]

Greg, I think that he wants his top link to be able to float as in you put your control lever in the float position. Can't do that when you have check valves. :laughing:

Sorry. I just can't grasp the concept of "floating" a toplink. My HTL had no check valves. It simply extended when I pulled the lever rearward, and retracted when I pushed it forward. The rod stayed where it was when I let go, at which time the lever centered itself automatically. What am I missing about this "floating" bit?

//greg//

 

[MtnViewRanch]

Sorry. I just can't grasp the concept of "floating" a toplink. My HTL had no check valves. It simply extended when I pulled the lever rearward, and retracted when I pushed it forward. The rod stayed where it was when I let go, at which time the lever centered itself automatically. What am I missing about this "floating" bit?

//greg//

As I understand it, some guys like to have the top link in float mode when mowing with a rotary cutter. Some guys like to put their top link in float mode to be able to push or pull the ram to where they need it to hook up the 3 pt hitch. Some guys talk about using float mode for pulling a scraper or whatnot. I don't think that works though, doesn't the implement just roll forward if there is no rigid top link? I think that if one has gauge wheels then you may be able to get away with either a floating top link or no top link at all as long as you don't take too deep of a cut, not real sure on that though. My opinion is that what eepete wants to do with his land plane will not work. The implement is going to want to curl up picking up the back of the plane, but without actually trying it I don't know for sure.

Does any of this make sense?

 

[The Tractor Guy 22]

My John Deere dealership in the Central Valley, CA told me JD doesn't make a TNT for CUT. They use the Gearmore system w/ Gearmore spools, or the popular way at JD is to use the Gearmore TNT with a Diverter kit which uses the front loader stick instead of the Gearmore spools. Not sure on my length, but I did loose some length when fully extended. Try calling Gearmore, they might have a good recommendation for you.

 

[Ductape]

Sorry. I just can't grasp the concept of "floating" a toplink. My HTL had no check valves. It simply extended when I pulled the lever rearward, and retracted when I pushed it forward. The rod stayed where it was when I let go, at which time the lever centered itself automatically. What am I missing about this "floating" bit?

//greg//

Say you have a finish mower, or bush hog on your tractor. It will have some type of 'play' where the top link connects to the mower, so that on uneven ground, the mower will 'float' and follow the contour of the ground. Now picture yourself coming to a steep incline. As your tractor starts uphill, but your mower is still on level ground, your toplink will run out of play (pretend it is a very steep incline). If you have a standard HTL and a float position on your remote valve, you can put the valve in the 'float' position (just like your loader), and the HTL will compress to allow the mower to float more than it normally would. With the check valve style HTLs, it takes hydraulic pressure to allow them to move..... they piston will not move in and out freely, even if you set your remote valve to the float position. Maybe this helps visualizing making the HTL 'float' ?

 

[greg_g]

What you describe is typically done with a flexible toplink bracket (on the implement) while the implement itself is pivoting on its lower lift pins. Again, that's mechanical float - not hydraulic. I've very honestly never seen a HTL with a terrain-following cylinder. But perhaps part of my problem is that I've never seen a toplink control valve with a "float" position either. All I've ever used are either the 2-way or 4-way open center types.

And within the context of my original HTL question, it's irrelevant anyway. Cuz unless I missed something, I can find no mention of rear SCV float in my JD3720 manuals.

//greg//