The top-n-tilt top link is already damaged. User error or poor design?

[mcmxi]

I was using the pressure washer to clean the MX this morning and noticed that the end of the top-n-tilt top link where it mounts to the top of the quick hitch looked odd. On closer inspection I realized that the outer ring has stretched into a rectangular oval if that's such a thing. I've been shortening the top link to pick up the rotary cutter to move short distances which obviously puts a lot of stress on that top link. I didn't think it'd be a problem but the Cat I/II design of the ball which has two holes and four faces means that the outer ring isn't fully supported by the inner ball as it is everywhere else on the tractor, and also on the two links that were replaced with hydraulic cylinders. Clearly there's nothing wrong with the weld since it looks solid, but that heim joint is a poor design.

You can see in the photos below that the outer ring has stretched and elongated under load. The local dealer gave me a new heim joint to weld on which is much stronger and has the standard single hole and ball that supports the outer ring. You can see the heim joint on the end of the top link that came with the tractor along with the new heim joint.

 

[Fordtech86]

Think I would have used a reducer bushing with the cat 2 hole with your size tractor/implements

 

[BigG]

The problem is using the top link on a rotary cutter that is as big as yours. You more then likely dropped the rear wheels of the tractor into a hole or ditch. This transferred a bunch of the weight of your unit to the front axle and to the tail wheels. When that happened the weight of the machines was forced to compress the top link and stretch out the opening.

The easiest way to avoid this is to remove the top link when you are mowing. But if you want to pick up the mower replace the top link with a piece of chain. The chain will allow the mower to be picked up and remove the compression stress on the top link.

I know you have a quick hitch and you could use the hydraulic top link to hitch up then remove the hydraulic top link and add the chain, However it is easier to forget the quick hitch shorten the PTO shaft and then run the mower.

 

[mcmxi]

Think I would have used a reducer bushing with the cat 2 hole with your size tractor/implements

Yes, that would probably have been stronger but it would still result in flats at the 12 and 6 o'clock positions allowing the outer ring to collapse.

 

[foobert]

The problem is using the top link on a rotary cutter that is as big as yours. You more then likely dropped the rear wheels of the tractor into a hole or ditch. This transferred a bunch of the weight of your unit to the front axle and to the tail wheels. When that happened the weight of the machines was forced to compress the top link and stretch out the opening.

The easiest way to avoid this is to remove the top link when you are mowing. But if you want to pick up the mower replace the top link with a piece of chain. The chain will allow the mower to be picked up and remove the compression stress on the top link..

Lotta speculation about driving into ditches and implements and such…

I’d love to understand better how a compression load has stretched the side of the heim joint that only sees tension loads

 

[mcmxi]

You more then likely dropped the rear wheels of the tractor into a hole or ditch. This transferred a bunch of the weight of your unit to the front axle and to the tail wheels. When that happened the weight of the machines was forced to compress the top link and stretch out the opening.

I was kind of thinking it happened the other way i.e. the weight of the cutter elongated the hole but I see what you're saying.

 

[mcmxi]

This photo shows the damage really well. That outer ring is supposed to be circular. Regardless of how it happened, if the ball were a complete sphere this couldn't have happened.

 

[foobert]

That heim joint needs to hit the gym and bulk up!!

Very poorly designed with such a thin walled outer ring that’s heavily point loaded by the square-edged “ball”. Just nothing to support it from collapsing.

 

[mcmxi]

That heim joint needs to hit the gym and bulk up!!

Very poorly designed with such a thin walled outer ring that’s heavily point loaded by the square-edged “ball”. Just nothing to support it from collapsing.

I agree and I'm going to replace it with the Cat II heim joint shown above and use a bushing. This is the Kubota top-n-tilt factory option so I'm kind of surprised they made them like this. They should have gone with Cat II and provided a bushing and be done with it. I've asked the dealer to pass these photos up the food chain but I don't know if that will happen. I did get the new heim joint for free but it's only $16 or so anyway.

 

[mikester]

This photo shows the damage really well. That outer ring is supposed to be circular. Regardless of how it happened, if the ball were a complete sphere this couldn't have happened.

View attachment 59663

Interesting design. Who is the manufacturer? I want them on my do not buy list.

 

[Crash277]

2% column A 98% column B, you might have been better using the cat2 hole however It looks like you eventually would have the same problem maybe just would have taken a bit longer, or not been as drastic. I’d mostly blame the design, isn’t enough ”round” on the ball with the extra flats.

 

[mcmxi]

Interesting design. Who is the manufacturer? I want them on my do not buy list.

The manager at the local dealership doesn't know who makes the top-n-tilt kit for Kubota and told me that it's unlikely that they'd give that sort of information out. It's sold as a Kubota kit so I hope they correct this issue so that others don't have the same problem.

 

[mcmxi]

2% column A 98% column B, you might have been better using the cat2 hole however It looks like you eventually would have the same problem maybe just would have taken a bit longer, or not been as drastic. I’d mostly blame the design, isn’t enough ”round” on the ball with the extra flats.

Ha! I can live with those numbers! I agree that using the Cat II hole would most likely have delayed the failure but not prevented it. I'm going to use a 7018 rod to weld on the new heim joint but no doubt it'll be a goat rope trying to get everything squared up. Fortunately I have the original top link so can put that on the tractor while the hydraulic version is being repaired.

 

[Crash277]

Ha! I can live with those numbers! I agree that using the Cat II hole would most likely have delayed the failure but not prevented it. I'm going to use a 7018 rod to weld on the new heim joint but no doubt it'll be a goat rope trying to get everything squared up. Fortunately I have the original top link so can put that on the tractor while the hydraulic version is being repaired.

i may very well be doing something similar in the near future. Finding a 16” hydraulic top link for under $400 seems impossible. However there are a pile of cylinders in the 1-200 range that require the ends be chopped and ball ends welded on.

there was a video where a guy made a jig to line up a cylinder IOT rotate the fitting to the side. I believe it was on a BX23S home made hydraulic thumb mod.

 

[mcmxi]

I have a DeWalt steel blade chop saw so If I can get the end of the ram cut square it should improve my chances of getting the new heim aligned in one plane at least. This is the time when I wish I had a nice horizontal band saw.

 

[mcmxi]

I got the damaged heim joint cut off fairly square, cleaned up the old weld, and used the quick hitch/receiver along with the link I made to align and hold the new heim in the correct orientation relative to the ram so that I could get a few tacks on. I need to finish weld the joint and paint. Probably going to run some 6011 in first followed by 7018.

 

[mcmxi]

I was able to finish up welding the new heim joint (6011 & 7018), paint it and get the cylinder and quick hitch back on the MX. Hopefully I don't have to revisit this problem. This is how it should have been in the first place. The local dealership manager (who bought my BX) is going to send the bad joint off to Kubota headquarters for them to review.

 

[mcmxi]

I wanted to give an update on the replacement top link heim joint that I welded on. I've put 25+ hours of hard mowing (rough terrain) with the 1,000 lb RCR1884 as well as a bit of box blade use on the new joint. I've raised the cutter off the deck many times and the joint is doing fine with no sign of impending failure. I run the rotary cutter with the top link connected. The first two photos taken this morning show the top link in its normal state. The bottom photo shows the top link this morning after wiping the crap off. 7018 for the win!!

 

[bcp]

The original joint seems to be one that was designed to be welded into a hole, not on the end of a rod.

Bruce

 

[BigG]

Nicely done!