3720 hydraulic toplink

[greg_g]

Lookin' for advice. Am shopping for a HTL for my new 3720, and want to make sure I get the right length. Definitely has to be a Cat 1, there's no room on the tractor bracket to pin a Cat 2.

I thought it would be a simple matter of measuring the OE turnbuckle toplink, but I was wrong. Tried hooking up several of my implements with it, and in doing so extended far more than I'm comfortable with. I'm not new to HTLs, I had a Cat 2 on my previous tractor. It was a hair long, so I'm wanting to do it right the first time on this new 3720.

The OE toplink is 18-3/8" closed (eye to eye). Given what I've seen so far, I know I need at least a 20" HTL. So I guess the question is; should I go to 22", or even 24"? I'm hoping for feedback from some JD3000 series owners that have already been where I'm at now.

//greg//

 

[Cocre]

I bought the following for my 3320. Somewhere on this site are some pictures.

https://www.surpluscenter.com/item.asp?item=9-7682-08&catname=

 

[greg_g]

Thanks, but I crossed that one off my list already, it's even shorter than the OE turnbuckle toplink. But Surplus Center has longer ones. I'm thinkin' the 24" will be too long, but was hopin' for feedback from folks who might have a 20" or a 22"

//greg//

 

[Cocre]

Thanks, but I crossed that one off my list already, it's even shorter than the OE turnbuckle toplink. But Surplus Center has longer ones. I'm thinkin' the 24" will be too long, but was hopin' for feedback from folks who might have a 20" or a 22"

//greg//

I have used mine for over a year. If I had to do it all over again I would buy the same one, and certainly not one any longer. The size is perfect for my box blade, my brush hog, and my tiller.

On my side link I bought a 6 inch stroke job, it I had to do that one over I would buy the 4 inch.

 

[jsboening]

My factory hydraulic top link measures 19.5" retracted and 25.5" extended. Seems to work fine with brush hog, back and box blades, and tiller. Not saying you have to go OEM, just wanted to give you the measurements.

 

[jimgerken]

Here's the best one I found:
HYDRAULIC TOP LINK CATEGORY 1 - Agri Supply

It started out in use on a 2520, but I kept it when trading tractors and then installed it on my 3720. So its probably 4 years old now, and has been used extensively. Works great, plenty of range, plenty of power. Very reasonable price and comes with the ball-joint ends and proper length. Before you ask, I am not sure what its range is, although I could measure it this weekend. And, I don't miss the load-handling check valve thing. In actual practice, I change the setting often enough to be able to ignore whatever slight settling might occur.

Good luck...

 

[Zebrafive]

Lookin' for advice. Am shopping for a HTL for my new 3720, and want to make sure I get the right length. Definitely has to be a Cat 1, there's no room on the tractor bracket to pin a Cat 2.

I thought it would be a simple matter of measuring the OE turnbuckle toplink, but I was wrong. Tried hooking up several of my implements with it, and in doing so extended far more than I'm comfortable with. I'm not new to HTLs, I had a Cat 2 on my previous tractor. It was a hair long, so I'm wanting to do it right the first time on this new 3720.

The OE toplink is 18-3/8" closed (eye to eye). Given what I've seen so far, I know I need at least a 20" HTL. So I guess the question is; should I go to 22", or even 24"? I'm hoping for feedback from some JD3000 series owners that have already been where I'm at now.

//greg//

I am having trouble understanding when you say your OEM extended "far more than I'm comfortable with" yet you want a top link cylinder that starts out longer than your OEM is closed. The HTL cylinders only get longer when extended.

Or are the 20", 22" or 24" extended lengths?

I would start with collapsed and extended length of OEM top link and make sure I could cover that with a cylinder. As to whether you need to be able to go shorter or longer I don't know.

Someone with more insight may be able to address the need to be able to go longer or shorter than the OEM top link

 

[jimgerken]

Lots of range in both directions (longer and shorter) can be usefull. Examples: If using a box blade, being able to lift the front way up makes it more of a trowel than a digger, making it possible to smooth the surface without gathering much soil. When I am working with a landscape rake in the woods trails, the elevational differences change dramatically from moment to moment. Like when crossing a ditch, sometimes it helps to be able to lift and then tilt the rake way up to help clearance. Other times I have to be able to drop and tilt it way down to follow a water break feature in a trail as I am traveling downhill over it. Another use for long range tilt is to extend a single box blade tooth, pull the bb tooth thru the ground up to a small stump, and then tilt the bb back as far as it will go, then retract again while pulling forward, and repeat. the stump will be pried from the ground by the tooth working against the bb cutting edge, powered by the hyd top link.
Ultimately, I think a guy would like to get a toplink that had a range of at least 6 inches, and its range should be centered where the ball end of the top link is extended to directly above the draft arm balls, 16 inches above them (cat 1). Hopefully that makes sense.

 

[greg_g]

I'm actually quite familiar with HTLs, I had a Cat 2 for quite a few years on one of the tractors I traded in against the 3720.

Anyway. The toplink that came with my 3720 is 18-3/8" closed (eye to eye). Toplinks of any kind are strongest when closed (screwed in all the way), and get progressively weaker as they're lengthened. And as a general rule, I transport my implements with the TL "closed". The OE toplink that came with the tractor is too short for that. Then once it's lengthened (screwed out) far enough to get my implements into their respective working positions, there's too much thread showing. Increasing length = progressive weakness.

The solution (for me) is a longer toplink. And yes, I've found Cat 1 HTLs as long as 24" closed. I'm trying to strike a compromise for a decent transport length closed, but not lose strength by having to open it too far to obtain working positions. I already determined that anything <19" closed is too short, but I'm sorta thinkin 24" may be too long. So I think feedback from the 20" and 22" folks would likely help me most.

I like the AgriSupply HTL as the rod is of a larger diameter than that Yugoslavian thing at Surplus Center. Larger diameter = greater strength. And 20" closed/28" extended sounds like a good range. I also like the extended tractor end. My other HTL had the ball end welded too close to the cylinder body, which caused the cylinder body to strike the tractor bracket in tight turns and high lifts.

That 19.5" factory HTL; John Deere factory? Frontier? The 6" extension seems a bit short. I typically extend up to 8" for some boxblade tasks. I've even found some Cat 1 HTLs that extend 10".

Gonna get a plumb line and test that idea about determining ideal toplink length based upon lower ball location. Thanks. Given previous experience though, I'm not sure 50/50 would work for me. My previous HTL usage never required more than 3" of retraction from full vertical for any implement in my inventory. It was a 10" Cat 2 cylinder, which I guess was split pretty much 30/70 (retract/extend). On an 8" Cat 1 cylinder, I'm thinking maybe 35/65 (?)

I'm presently leaning towards that 20" AgriSupply HTL, but hate to make a move without hearing from someone that may have experience with a 24"

//greg//

 

[MtnViewRanch]

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.

 

[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//