Catastrophic hydraulic top link failure

[pclausen]

I was driving down a blacktop road and then I hit a transition to gravel and there was a little bump (I have driven across this transition dozens of times with various implements). This time I happened to have my stump grinder attached. I was going maybe 10 mph.

Here's what happened to the top link:

Not sure if you can make out the letters, but is was a forged eye.

The stump grinder dropped to the ground and was coasting on the cutting wheel until I came to a stop to investigate what happened. After pulling over, I walked back to the shop and got my manually adjustable top link and was back in business and the stump grinder still works fine. Whew.

If I had had my 2200 lbs chipper mounted on the back when it let go going down the road at speed, that could have been really bad.

Was this likely due to metal fatigue of some sort, and would it be likely to happen again if I replace with the exact same make hydraulic top link?

 

[jenkinsph]

I suspect it was a fluke, I would get the replacement and move on. If it happened a second time I would change cylinder brands.

 

[radioman]

I agree with jeninsph. It could be pot metal they used or it was under stress developing a stress fracture when stump grinding. Either way - it may not be strong enough for your uses/needs. Perhaps you can weld on a new eye of a different brand and call it a day. If it happens again with a new stronger welded on eye - I'd start upgrading the unit.

 

[CharlieS]

looking at that eye, i'm thinking its simply not heavy enough even for a cat 1 toplink. I use both cat 1 and 2 toplinks depending on the tool attached and the cat 1 link looks to be way heavier than that. as for being pot metal, thats rubbish. the mfgr would be leaving themselves open for all kinds of lawsuits.

 

[TCJatko]

Looks flimsy to me. I'd suggest a different brand.

 

[mikehaugen]

sucks you would have to replace the whole piston rod since it isn't a threaded on eye, are they all like that?

 

[Dave M7040]

Can you post a closeup of the fracture surfaces on the top link.
Dave M7040

 

[aczlan]

sucks you would have to replace the whole piston rod since it isn't a threaded on eye, are they all like that?

Not a big deal to weld on a new one, just run it all the way out and cover the whole rod with wet rags to keep the seals cool and the rod spatter free.

Aaron Z

 

[JD 4520]

I would say it could be a fluke, it is likely from a stress fracture and it is definitely light weight for a 2200 lb implement. I would try to find someone that can weld a new eye on as long as they know what they are doing and you get a cat2 eye otherwise look to upgrade when you replace it. That is a lot of weight when you took a bounce and likely previously fractured slightly.

Let us know what you decided on.

 

[Baby Grand]

I agree with jeninsph. It could be pot metal they used or it was under stress developing a stress fracture when stump grinding. Either way - it may not be strong enough for your uses/needs. Perhaps you can weld on a new eye of a different brand and call it a day. If it happens again with a new stronger welded on eye - I'd start upgrading the unit.

Not a big deal to weld on a new one, just run it all the way out and cover the whole rod with wet rags to keep the seals cool and the rod spatter free.

Aaron Z

I'd consider the above advice as the path to follow. Get a beefier rod end and take it to a good weld shop if you're not comfortable doing a multipass weld without porosities or cold shuts in your own shop. That rod end looks a bit delicate for going over bumps at speed with a 2200# implement dangling off the top link. Is that a class 1 or 2 top link?

 

[crazyal]

What's the other eye look like? Does it show any signs of failing soon? I'm not sure if I would weld a new one on not knowing if the other end was going to hold up. You could take the cylinder apart and weld on new ends on each side, maybe something stronger.

 

[ray66v]

Not a big deal to weld on a new one, just run it all the way out and cover the whole rod with wet rags to keep the seals cool and the rod spatter free. Aaron Z

Agreed. :thumbsup:

 

[Zebrafive]

You did not say the weight of the stump grinder, only good thing it was not the 2200lb chipper.
I too wonder the condition of the tractor side end.
For that size tractor it should be CAT II, not CAT I
Have you contacted seller about replacement?

 

[srs]

Sure glad no damage was done to the tractor; glass, fenders, etc! You've been through that before.

 

[PILOON]

Stretched as that eye is I do not think it is forged or hardened. Perhaps it missed a step in the welding process.
Generally a hardened or forged part would snap and not elongate. Might be a warrantee case.
Do a spark test using a grinder.

 

[MBTRAC]

Whilst rare, it's not entirely uncommon for hydraulic cylinder eyes to let go - however when they let go it's usually a clean break from a stress crack or porosity in the metal.

As other have suggested the elongation/stretch indicates either a manufacturing &/or design error - and as the component was not fit for purpose, potentially under our (Australian) consumer laws as a safety issue, cause for invoking a mandatory recall by the manufacturer/importer

 

[pclausen]

Here's a closeup of the metal surfaces that broke.

I too am very glad it didn't happen with the 2200 lbs chipper attached! My stump grinder weigh a little over 1000 lbs. My Bush Hog 3209 cutter weigh as much as the chipper, maybe even a little more. I also recently got a Valby 3pt log grapple that could have put a lot of stress on the top link when lifting logs off the ground.

The top link is a 3" cylinder and cat2 specs as far as the pin dimensions, etc.

I did contact the seller and a replacement is on its way at no charge. It also incorporates a different design with beefier ends.

srs, yes, I certainly have been though a lot worse than this before!

 

[JD 4520]

Great outcome with the vendor.

 

[aczlan]

I did contact the seller and a replacement is on its way at no charge. It also incorporates a different design with beefier ends.

Who is the seller? Sounds like a good company to do business with.

Aaron Z

 

[SSdoxie]

just one of those "flukes" that happen now & then. good to hear company is standing behind it. Are they sending complete new cylinder or just the rod? If it is complete cylinder and they don't want the old one back, someone on here might be interested in taking it off your hands for nominal fee and weld a new end on it. Not me though, I've got one.