Broken lower link pin on Kubota L5450

[txody]

One of the lower link pins failed while mowing (a fatigue crack, I'm told). The pin broke off just slightly inside the gearbox housing and will not budge ... even after I removed the retaining bolt, plate, and nut.

Two dealers have assured me that there is nothing else holding the pin in place (e.g. no threads on the pin still inside the housing), but I'm afraid to pound too hard on something lodged in a cast housing. Unfortunately, the new part is a "redesign" so it may not be identical to the original, and the other original pin doesn't want to be removed either.

Anyone familiar with this setup or have ideas on how to get the old piece out?

Thanks

 

[HammerFour]

Drill a hole in what's left, tap it, thread a bolt in there and then use a slide hammer or something on the bolt to tug it out?

If there is enough sticking out, weld a piece on it that you can get a grip/more leverage on? The heat from welding might loosen it a bit as well.

If you have access to a big enough area, there is always the dremel with the cutting disc on it...cut it into pieces and remove it but I don't think it sounds like you have enough room for this.

 

[slowzuki]

I'm not familiar with the exact tractor but I'm guessing the pin slides through one cast "tang" then through the lower link ball, then into the main casting. The ball yanked the middle section of the pin out leaving the part in the outer tang.

Because the pin deformed when ripped out it is a good idea not to pound it out really hard, you may break the tang off. Drilling the centre of the pin out if possible is one option. Another is heating the tang and hope the pin can be slid out (don't pound when it is hot!)

Also you could get a torch and burn straight through the pin and eat away at it, once most of the pin is burned out it will come easily.

Another option is to try a 2 jaw puller to push it through, this combined with some heat is the least scary for most.

Personally I'd burn the guts out of the centre with the torch. /forums/images/graemlins/cool.gif

 

[RichNJKubota]

I vote for burning it out with a cutting torch.

 

[rbargeron]

Brad,

The pin goes through the ear on the housing (about 2" thick) and there is a nut on the back side. Here's a pic that almost shows it:

The illustrated parts list shows the pin as smooth where it goes thru the casting - with the nut removed it should knock out from the back. Might need a drift and hammer to get it started out. Hope this helps.
Dick B

PS: At TBN we don't hesitate to jack up our tractors and take 'em apart to show another member a better view of things!! (kidding - this pic is from my 2-speed pto project /forums/images/graemlins/cool.gif

 

[txody]

Thanks for all the suggestions. Sounds like everyone agrees the pin should slide out, and is just rusted or otherwise siezed.

The picture attached by rbargeron is really quite helpful in describing the problem ... I'll remember that for the next posting as I seem to be really good at breaking stuff. Some clarification based on the picture: the left pin broke flush with the cast tang (the bearing surface and the larger diameter shoulder came off, beneath the stamped steel bracket visible in the lower left of the photo); the threaded end extends beyond the center-side of the tang by about 3/4 inch, and the top third or so is "hidden" by the bottom of the casting ... the nut is unthreaded, but can't be completely removed until the pin slides out. What this means is that the pin must go to the outside, and cannot go to the inside.

An update: I filed two sides of the threads flat to get a grip on the pin so I could try to twist it loose, but no luck. Maybe I could tap a hole an use a large bolt to twist it with a breaker bar? I did pick up a 2-jaw puller this evening (and some new super-duper breakfree spray), and will try that tomorrow. Hopefully the jaws will grip on the steel bracket and not on the casting. If that doesn't work, I guess I'll remove the wheel to make room for a slide hammer.

I need some help on the burning idea. Is there anything I should do to keep from burning the cast tang? Or is this something best left for a professional, as my welding/torch experience is minimal?

Thanks again. Brad/txody

 

[slowzuki]

If you aren't handy with a torch I wouldn't burn. When you have two surfaces together there is a little delay between cutting into the 2nd surface as the preheat takes a while. You can, if really good, burn out the entire pin without damaging the tang surface. Part of the key to doing this is being fast and confident. Take too long and the tang heats up and is easily cut.

 

[rbargeron]

I'm with Ken on using heat. Have someone do it who has done it before. The tang is part of the final drive planetary gear housing. It's replaceable, but wouldn't be cheap.

It is possible that Kubota has used an adhesive (something like Loctite) to help hold the pin in place - if so, a moderate heat-up might work to loosen it. Here's a Q & A from Loctite's website:

" Q: How can I remove a fastener that is "permanently" locked in?

A: The application of heat is needed to remove a fastener that can't be removed with a hand tool. Temperatures of 325F and above is needed to break down a standard anaerobic, 500F for high temperature Anaerobics. A heat gun or propane torch is commonly used to do this process, and careful disassembly should occur while parts are still hot. Once apart, and cooled, use methylene chloride (Chisel #79040) to remove cured excess material. Always wipe down the fasteners with clean up solvent to remove the wax film that Chisel leaves on the surface."

Maybe you could arrange a threaded "pusher" that could be tightened as heat is applied. A 5/8"or 3/4" bolt with a nut & washer running against a pipe sleeve to the other side might give you some steady force to augment the heat. /forums/images/graemlins/confused.gif

 

[txody]

Success. Thanks for the ideas and the encouragement to keep going. I would have spent a LOT of money without you guys.

No room for the 2-jaw puller (but a cool tool to have around now). The pipe/screw sounds like a trick to remember for the future. Turns out nothing holding up the process but a close tolerance and a bit of rust under pressure. Local shop recommended some anti-sieze paste for all lower end items when replaced.

The solution: a 1/2 x 7 inch bolt (head for pounding and shaft for holding) and a hammer ... plus a lot of short-stroke hits ala Uma Thurman in "Kill Bill."

For reference, here is the considered advice of Kubota's Tech Response I received today after 7 days: "Thank you for your email regarding your L5450. Without a physical inspection of this unit it is not possible to supply helpful technical advice. There no "tricks" to removal of the part you indicated. We do recommend you bring the unit to your authorized Kubota dealer for assistance completing this task. They will have the tools and training to effectively facilitate repair." I just can't seem to follow instructions ....

Thanks again; hope I can return the favor some day.



The attachment shows the bad boy and the high tech tools that gave him a spanking.