MX5400 Top Link

[Camoranger0764]

Good Morning Everyone.
I recently purchase a New MX5400 CAB Tractor. Not new to Kubota Tractors, I have had several, but "Need Some Help/Info" .
For some reason "Everything " I try to hook up the Top Link to has to be almost all the way out.. It's like the Top Link is not for
a Tractor with Telescopic 3 point hook up. Please Help.

Thank You;

 

[mcmxi]

Why are you concerned about the top link being extended? The top link is under tension (mostly) so as long as there's full thread engagement on both threaded rods on either end you should be fine.

The top link shown below on my MX6000 is 28" from pin to pin with the QH15 attached and a snow blower on the QH15. I typically run a top-n-tilt system on both tractors which has an hydraulic top link, but some implements need two hydraulic circuits so I have to figure out what is more important. For the snow blower I like the hydraulic tilt with float so use a solid top link.

 

[edritchey]

Good Morning Everyone.
I recently purchase a New MX5400 CAB Tractor. Not new to Kubota Tractors, I have had several, but "Need Some Help/Info" .
For some reason "Everything " I try to hook up the Top Link to has to be almost all the way out.. It's like the Top Link is not for
a Tractor with Telescopic 3 point hook up. Please Help.

Thank You;

Those extendable links are only made to do so to make it easier to hook up attachments after it's hooked up you should lock those back into their closed position they are not design to stay extended during the use of your 3pt attachments.

 

[Camoranger0764]

The Part I'm worried about is, You shouldn't have to extended them all the way out to hook up a Attachment. When Your Top Link gets Adjusted all the way out or right at the End of the Threads.
Your Top Link is Weaker and Your asking for trouble with the Threads. I have 2 Other Tractors L3540
and MX5100 both with Factory Top Links. Both or Longer. Leveling out My Box Blade or My Bush Hog
That Top Link has to be set and locked down. You Can't lock them back all the way to the closed Position. My Dealer is checking on it now. It seems that Kubota shipped some MX Models with too short of a Top Link.

 

[mcmxi]

The Part I'm worried about is, You shouldn't have to extended them all the way out to hook up a Attachment. When Your Top Link gets Adjusted all the way out or right at the End of the Threads.
Your Top Link is Weaker and Your asking for trouble with the Threads. I have 2 Other Tractors L3540
and MX5100 both with Factory Top Links. Both or Longer. Leveling out My Box Blade or My Bush Hog
That Top Link has to be set and locked down. You Can't lock them back all the way to the closed Position. My Dealer is checking on it now. It seems that Kubota shipped some MX Models with too short of a Top Link.

How long is the top link on your MX5400 when it's hooked up? I measured the top link for my M6060 and it's also around 28" fully extended. There's only about an inch of thread engagement at either end of the link and so as long as you have that full inch all is good. It makes no difference if the link is at 20" or 28" since it's in tension.

 

[BAP]

The further out your toplink is adjusted, the easier it is for them to bend. Yes, toplinks can bend.

 

[mcmxi]

The further out your toplink is adjusted, the easier it is for them to bend. Yes, toplinks can bend.

The bending (buckling) of the top link is a function of the cylinder dimension between the threaded rods because the loading is axial. There's only about 1" of thread engagement at either end of the rod so the threaded sections make no difference to the buckling of the cylinder as long as there's full thread engagement. If the loading is radial then yes, the length of the link makes a difference to bending, but the loading isn't radial, it's axial.

The top link is mostly in tension, but if you're pushing a snow blower into a snow bank, or a box blade into a pile of dirt the top link can/will be in compression. But once again, the direction of the force is axial and not radial.

 

[BAP]

The bending (buckling) of the top link is a function of the cylinder dimension between the threaded rods because the loading is axial. There's only about 1" of thread engagement at either end of the rod so the threaded sections make no difference to the buckling of the cylinder as long as there's full thread engagement. If the loading is radial then yes, the length of the link makes a difference to bending, but the loading isn't radial, it's axial.

The top link is mostly in tension, but if you're pushing a snow blower into a snow bank, or a box blade into a pile of dirt the top link can/will be in compression. But once again, the direction of the force is axial and not radial.

Doesn’t make any difference what kind of fancy names you put to forces that can bend a toplink. In my 40 plus years of farming, I have seen toplinks bend when you least expect it and the longer they are extended, the more likely they are to bend, particularly when using a 3 point hitch mounted tillage equipment.

 

[GreensvilleJay]

I pulled 2 bent toplinks out of a scrap bin one day. Cut off the ends,welded HD pipe as the center section. Kinda impressed with the amount of RUST inside the original, thin tube.....probably why they bent.
Interesting 'extendable' lower arms,watched a video, not convinced it's easier though..seems more of a 'gimmick'.

 

[Camoranger0764]

Thanks Everyone for the help. The Dealership has been Great. They’re working on getting me the next size up in length. They’re also in total agreement we some of us here. It’s not good nor recommend to run the Top Link fully extended.

 

[mcmxi]

Doesn’t make any difference what kind of fancy names you put to forces that can bend a toplink. In my 40 plus years of farming, I have seen toplinks bend when you least expect it and the longer they are extended, the more likely they are to bend, particularly when using a 3 point hitch mounted tillage equipment.

My dad was a farmer and I've been around steel, welding and engineering for over 40 years but so what. As @GreensvilleJay says, the quality of the tube plays a big part, and of course the loading.

Those "fancy names" are used every day in the design of buildings, satellites, cars, trucks, tractors, rockets, rovers, and so on. It's called engineering and math and there's a reason why a cylinder fails under axial load. It's well understood, it can be accounted for, it can be designed for. Of course a top link can bend given enough of an axial load or unexpected abuse. But not understanding why it bends and what the major contribution to the failure is means that you will be doomed to repeat it, which you clearly have.

 

[mcmxi]

Thanks Everyone for the help. The Dealership has been Great. They’re working on getting me the next size up in length. They’re also in total agreement we some of us here. It’s not good nor recommend to run the Top Link fully extended.

Yes, because dealers are a reliable source of information. Odd that Kubota doesn't mention the risk of extending the top link other than the chance of it coming apart if it's extended beyond the groove in the thread. But you don't strike me as being someone interested in facts, just looking for someone to tell you what you want to hear. No doubt you've been around tractors for 40 years too.

 

[jyoutz]

I pulled 2 bent toplinks out of a scrap bin one day. Cut off the ends,welded HD pipe as the center section. Kinda impressed with the amount of RUST inside the original, thin tube.....probably why they bent.
Interesting 'extendable' lower arms,watched a video, not convinced it's easier though..seems more of a 'gimmick'.

Not a gimmick at all. The extendable arms make implement hook up easy, so easy that I decided against a quick hitch

 

[hedgerow]

Good Morning Everyone.
I recently purchase a New MX5400 CAB Tractor. Not new to Kubota Tractors, I have had several, but "Need Some Help/Info" .
For some reason "Everything " I try to hook up the Top Link to has to be almost all the way out.. It's like the Top Link is not for
a Tractor with Telescopic 3 point hook up. Please Help.

Thank You;

I like you don't care for the length of the top link on my MX- 6000 so its hanging on the peg board in the shed. I ended up custom building one that fits my needs better. I don't adjust my top link much so I didn't need a hyd one.