Broken bolt

aczlan · Feb 5, 2017

ovrszd said:
Grease has nothing to do with that bolt shearing. Look at his picture carefully. He has an arrow pointing at the grease zerk. If that joint is over greased it will simply squish out around the bottom edge of the cap. I grease mine until it does.

The large bolt that he circled is the one that is broken. That is a very serious breakdown. The tractor should not be used again until that's repaired. By used I mean don't drive it at all. Tomorrow morning you need to call your dealer or visit them with pictures. They will have to service the tractor where it's sitting.

Excellent advice. If the other bolt fails or the bracket bends, it could cause the gears in the axle to bind/rip apart and that would be a very bad thing.

Aaron Z

ovrszd · Feb 5, 2017

aczlan said:
Excellent advice. If the other bolt fails or the bracket bends, it could cause the gears in the axle to bind/rip apart and that would be a very bad thing.

Aaron Z

Yep. Be hard to explain to the dealer why you drove the tractor knowing fully well the front hub assembly is falling off.......

Spud68 · Feb 5, 2017

Lots of good info here. I plan to call the dealer in the morning as soon as they open. I would think they could just send a truck out, remove the broken part of the bolt and check the hub and replace 2 bolts. should take no longer than a couple of hours. you would think.... BTW here are pics of the bolt head and shaft that came out. Notice the head has never been touched after they painted it so they cant say I was messing with the bolt.

ovrszd, I also paid a premium for the warranty so I didn't have to worry about stuff like this. just sucks to be just getting ready to start her up and do some work and then a big POP while greasing the fitting. I was looking for the grease to come out of the bottom and then bang. oh well now to the pics....

BTW if anyone wants to take a gander of my little retirement project here is our Facebook page chronicling the project from cutover to homestead.
Reynard's Hollow | Facebook
Its called Reynard's Hollow.

Thanks again for all the great advise and help!
Teddy

aczlan · Feb 5, 2017

I would have them chase the threads with a tap before they put a new bolt in to make sure the bolt didn't mess up the threads on the way out.

Aaron Z

oosik · Feb 5, 2017

That pic on the left - the bolt has an unusual appearance. Stress failure or stress fracture doesn't normally produce a bolt that looks like that. That bolt looks like its been squeezed and sheared off.

MHarryE · Feb 5, 2017

BOLT FAILURES

You might want to take a look at this link. Compare your bolt to Figure 3. Appear to have the same 45ｰ shear plane typical of an overload failure.

http://www.boltscience.com/pages/Failure Modes.swf

The second link - go to slide 7 to see the same type of failure mode, also shown to have resulted from overload.

s219 · Feb 5, 2017

I don't think the bolt was over-torqued, as that would have left somewhat of a helical fracture surface. In this case, it looks like it was an extreme tension load along the length of the boat. How the heck could that have happened? I am having a hard time envisioning a situation where that bolt would get an extreme tension load.

Might be interesting to see a closeup photo of the fracture face, to see if there is an obvious defect in the bolt. If that were the case, I'd expect it to fail in torsion when being torqued down, but who knows.

oosik · Feb 5, 2017

s219 - exactly my thoughts also. I can't figure how a bolt at that location would be subject to a load that would shear it off or stretch it like that. There could well be something else going on here. I figured the head of the bolt would be just popped off but that picture casts a different light on this situation.

Teddy - I would be sure that the dealership gets a chance to see that bolt - shown in your pictures. I would want them to determine the cause of this problem and not just replace the bolt. I would also have them check all the bolts on both sides for signs of failure.

olPete · Feb 5, 2017

oosik said:
s219 - exactly my thoughts also. I can't figure how a bolt at that location would be subject to a load that would shear it off or stretch it like that. There could well be something else going on here. I figured the head of the bolt would be just popped off but that picture casts a different light on this situation.

Teddy - I would be sure that the dealership gets a chance to see that bolt - shown in your pictures. I would want them to determine the cause of this problem and not just replace the bolt. I would also have them check all the bolts on both sides for signs of failure.

I reckon you could lift the whole tractor by that bolt and not break it to look like that. Will be interested to keep following this one til we hear the dealer's findings. Looks to me like both a dud bolt and overtorquing? Because if it was a branch or something that hit, I'd think the tractor would still be parked on it

I have one that looks similar and it took major operator failure to do that.
To put my error into perspective...
I may have clipped a concrete post with an 8' side mower while mowing silage. Hit the frame just at the end..
The frame has already had a hard time. That's why I bought it for $50.. its mounting bracket is 6 inches square as was held on by 4 12mm bolts, that's a touch under a 1/2"... two were already snapped off in the casting, one bent and had a crack between the threads but I got it out with no trouble, the other looked like the one in the OP's picture. Welded on a ring spanner to get it out as it was well seized in there. So that's a huge amount of leverage across a small area, plus half the bolts already gone, to get a 45° shear on a much smaller bolt.