Broken bolt

[ovrszd]

Me too.

I work the snot out of my M9540. 1100hrs. Majority of those hours doing FEL work with a Grapple. Many, many times with one rear tire off the ground. The basic design of these front axles is very strong and proven.

There's something very unusual about this failure.

I'm glad you caught it while greasing the tractor rather than when carrying a heavy load.....

 

[s219]

S219, here is a closeup of the bolt face. I am really interested to find out the cause as well.

View attachment 497748

Teddy

Well, it looks like the outer part of the bolt, where you see the zig-zag of the threads in the upper-left of the photo, has both a shiny appearance and some rust, which suggests it was cracked for a while. The shiny part would have come from the metal rubbing against itself, and the rust from exposure. Hard to say from the photo -- does it look like that to your eye? The inner part looks more like a fresh fracture. As to what caused the original crack, hard to say. It's possible the heat treatment was not right, making the bolt susceptible to fail in this unusual way. Don't see any defects in the freshly fractured portion.

One possibility is that the bolt went in off-kilter for some reason, either cross threaded, or the receiving tapped hole was not perfectly perpendicular to the surface, or the bolt threads were not cut right, and then when the head was snugged down flat, it bent the bolt. Does it perhaps look like it may have gotten bent slightly? Any indication the threads took abuse? That would probably lead to the type of fracture seen in the photo.

 

[ovrszd]

To me, in his first pic of the bolt, it looks bent. But that could have happened as it broke?

 

[dodge man]

If you look at the link posted above, they show a pic of a bolt failure that is similar. It says its usually caused by another problem, one being the bolt actually not being tightned.

 

[Ford850]

Improper chain location, or chain binder over tightened. ??

 

[ovrszd]

Improper chain location, or chain binder over tightened. ??

Please elaborate??

 

[olPete]

To me, in his first pic of the bolt, it looks bent. But that could have happened as it broke?

At a guess. And only going by what my eyes tell me, that bolt had been partly cracked/fractured since it was installed, and just part in the middle is fresh. So it has probably been slightly bent if it's only been holding by a small area. Hard to say, only have a tiny screen but it sure wasn't grease pressure that did it, would it have been lashed down across the front axle, perhaps if the machine has nowhere handy as a lashing point, that it would be held down by a strap over there?
It's a job for the dealer to remedy, both sides!

 

[ovrszd]

Understand that the downward pressure of the tractor on this bolt pulls the two castings together, rather than pulling them apart. The more downward force applied, the more the two pieces press against each other.

So, unless you chain down the front tire assembly. Then chain down the tractor chassis separately. You can't create a force that would shear this bolt.

From what I see, there's much more going on here. Anxious to hear the results of the dealer's repair.

 

[olPete]

Agreed. I've just seen a number of really really big machines hauled and held down by the wheels and thought it may be a possibility. Am on the big screen now and realize it's not even the bolt I thought it was

 

[aczlan]

Agreed. I've just seen a number of really really big machines hauled and held down by the wheels and thought it may be a possibility. Am on the big screen now and realize it's not even the bolt I thought it was

The only way I could see that happening is if a chain was run over the top of that knuckle while the tractor was on the skid in transit across the ocean. Then I can see something being run over that point. Even then, I think they're bolted into the skid, not chained down.

Aaron Z