Loader "pivot" bolts

[hunt4570]

Ok, Kubota 3540W LA724 loader, owned it about 6 months. 450 hrs

Look at the pics cause my terminology is most likely wrong . You will see the pivot pin working its way out of the hole, this is the second time I've had to replace the bolt holding it in. Granted I replaced it with probably a grade 2 bolt I had in the garage, now my question..

Should I replace it with a grade 2 (shear bolt) or go with a grade 8? Do I really need it to shear at this spot? I'm thinking not. Also... is there some underlying problem going on here I need to attend to? I'm the second owner of this tractor and it only has about 450 hrs on it

And yes I grease those.

Thanks.

 

[SPYDERLK]

Go to grade 5 and be sure the shank goes completely thru both shear points so only the shank sees shear stress. You do not need shear protection here but you certainly dont want bolt failure. Use the largest dia for the hole. Keep up the greasing.

 

[Valbird]

Consider pulling the pin and looking in the cylinder attachment bore, and see if there is anything not smooth, or which would otherwise contribute to a rotational shear force on that pin.

Barring that, I would look at the Kubota part and determine the bolt grade.

 

[LD1]

ITs not a shear bolt, rather a bolt to keep the pin in place AND keep if from rotating in the bucket frame where it isnt greased. ITs greased in the loader frame and thats where you want it to spin.

The underlying problem is lack of grease. IF it spins freely, you wont break that bolt.

 

[Leejohn]

You said you grease it, but is the pin getting the grease? By the picture it looks like it is not, pull pin clean the holes out and put a new grease fitting in.

 

[Leejohn]

Looks like we jump on that at the same time.

 

[crashz]

Looks like you replaced a few of the retaining bolts with longer ones. Could the bolt and nut have sheared off at the boom stops? Seems like that could have caught it if the long end was down.

 

[hunt4570]

The longer bolts were there when I bought it.

I grease through the zert and stop when grease comes out one side, so I'm sure its getting grease.

Think I'll go through and replace all these bolts.

 

[Valbird]

The longer bolts were there when I bought it.

I grease through the zert and stop when grease comes out one side, so I'm sure its getting grease.

Think I'll go through and replace all these bolts.

That is not always the case. I have seen a dam of polymerized grease and dirt stop the flow of grease in a plain bearing. That is why I suggested pulling the pin and looking at the end on the cylinder.

While you are there, you can clean it out with a power washer or rags and solvent. Get it real clean, and make sure the wear pattern looks normal and the surfaces smooth. Then oil it up, reassemble and grease it.

That is at least how I would approach a problem similar as to what you describe.

 

[k0ua]

The question I would have is what happened to the bolt? Did it just fall out? All it has to do is just keep the pin in. There should not have to be much force on it. The original had a type if lock nut with plastic in the top of the nut to help prevent loss of the nut from vibration and hence loss of the bolt. The nut is not normally tightened down, and the bolt is free to move up and down in the hole. But is retained by the locknut. As others have noted, the pin does not appear greasy. It should be.

 

[CCWKen]

I don't see grease either and no sign that there was any grease on that pin. I would do as mentioned already and pull the pin and clean it and bore of rust. Your method of greasing isn't getting the job done. Failure to keep the pins greased will result in some expensive bushing replacement.

 

[hunt4570]

Probably good advice, thanks.

I'll have to drop the bucket, and the weight, and start pulling pins to clean them up.. I need a maintenance day anyway..

 

[Stimw]

No one has mentioned it but what grease are you using?
I have a grease pump and grease a lot of machinery.
I will only buy a grease that has "EP" (Extreme pressure) rating.
I have been buying Valvoline in 5 gal buckets from NAPA.
I also only buy red grease so there is no doubt that I greased an area if a customer questions it.

 

[Valbird]

The question I would have is what happened to the bolt? Did it just fall out? All it has to do is just keep the pin in. There should not have to be much force on it. The original had a type if lock nut with plastic in the top of the nut to help prevent loss of the nut from vibration and hence loss of the bolt. The nut is not normally tightened down, and the bolt is free to move up and down in the hole. But is retained by the locknut. As others have noted, the pin does not appear greasy. It should be.

That information on the bolt with a loose plastic locknut is good. I would emulate that. If using a Grade 2 or Grade 5 bolt, and tightening down a nut is breaking, then I would be suspicious that there might be some dimensional changes to the flange. Use a nylon lock nut, or use two nuts locking against each other, making the bolt a loose fit.

But I repeat again, pull the pin and inspect it for a normal wear pattern, for no polymerized grease and dirt, etc. Reassemble with machine oil, and then grease with the bucket unloaded.

 

[hunt4570]

And I'm guessing the bolt broke, yes it had a stop nut on it.

And I'm pretty sure its EP rated grease...

QUESTION: My grease gun... seems like its got a airlock or something. Decent gun, can use tubes or bulk fill. new tube of grease... nothing, nada, pump the handle and no pressure at all... messed with it and messed with it, am just about ready to toss it and get another, even though its about new!:hissyfit:

 

[Stimw]

I HATE GREASE GUNS! I have fought with them for years and don't even think about using one on a cold day!
I have found that if I make the hose hand tight then I can un-screw it, put my finger over the end of the gun where the hose goes and pump it will pick up pressure again.
It's like they get an air bubble and won't pump it out. Once I get pressure I put the hose back on and it will work.

 

[Looking4new]

I HATE GREASE GUNS! I have fought with them for years and don't even think about using one on a cold day!

I use 'winter grease' year round in my gun and it works good.

 

[Leejohn]

I HATE GREASE GUNS! I have fought with them for years and don't even think about using one on a cold day!
I have found that if I make the hose hand tight then I can un-screw it, put my finger over the end of the gun where the hose goes and pump it will pick up pressure again.
It's like they get an air bubble and won't pump it out. Once I get pressure I put the hose back on and it will work.

When you put a new tube in don't screw the body on all the way. Then release the rod and push it in. Let the spring push the grease in, pump the handle a few times and it should help. After you get good flow of grease screw the body all the way on.

 

[crashz]

Leejohn is right, the loose top section will allow air to escape.

When I replied yesterday, I wrote how I felt the regular greasing was not regular enough. I erased it because it sounded too harsh. But some posts were much worse. I should have left it in to cushion the blow!

I'd be curious to see what's rotating and what's not in this case. Maybe try rotating the bucket and watching the pin while unsecured. Does it rotate with the bucket or stay still? Will a sacrificial pencil hold the pin while rotating? My thinking behind this is that a dry pin connection with enough force to break a Grade 2 bolt would screech like mad if it was the pin/bushing resisting.

Me thinks that you'll find external forces at work here (aka - long bolt sheared off)

But ... as stated before by Valbird, I'd pull it apart, clean and inspect before re-assembly and generously greasing. Greasing is always a sloppy mess and should be done with each use. If you don't see clean, liquid-ish grease on all joints, at all times, you aren't greasing enough.

 

[k0ua]

The question I asked and did not see an answer to is how do you know the bolt broke? Did you find a sheared off bolt? Did it just fall out from loss of the nut?