JD 2520 Snapped Axle

[jenkinsph]

I don't find it hard to believe.

Nor do we know if a catastrophic impact happened that over stressed the casting at a time before the actual failure. Or even related to the previous failures or their repair. Many, many unknowns here.

I find it difficult to form much of an opinion on matter but I really can't imagine that I could have a problem like this and have a skid for this duration. For most operators that are paying attention I think you would have stopped the machine long before it was dragged sideways this far.

Sorry to say it looks like abuse to me, glad my opinion is worthless though.

 

[slowzuki]

Aluminum has a fatigue life and gets weaker as its cycled but it should be designed for it. I can't say its abuse as it looks to be used exactly what CUT's get used for. I don't think if I was a landscaper I'd want to try that model.

 

[Dutch445]

OP Where Are You??????

from your first post:
"This will be the 4th and most substantial repair, having once sheared
a drive gear on a front wheel, and twice replaced the outer drive gearbox
housings on the rear wheels."

was all this done under warranty? what was the cause of these
failures?
something doesn't sound right

 

[RoyJackson]

Aluminum has a fatigue life and gets weaker as its cycled but it should be designed for it.

Think about that statement the next time you're flying a 25 year old airliner with 50000 flight hours.
BTW, the cycling of the airframe is mostly (but not completely) due to pressurization and depressurization of the fuselage.

 

[PapaPerk]

Think about that statement the next time you're flying a 25 year old airliner with 50000 flight hours.
BTW, the cycling of the airframe is mostly (but not completely) due to pressurization and depressurization of the fuselage.

Aluminum has a far lower fatigue life than steel. However if you are well below the endurance limit of the material, the fatigue life should be near infinite.... or at least beyond the life of the rest of the machine.

So the question is... are the parts exposed to stress above the endurance limit? And for how long.

 

[slowzuki]

I'll repeat, split your brakes and set your cruise control and try and stop with one brake on damp soil. It will leave a skid mark just like that one. You don't even need to be going very fast to do it. Unless you creep around at idle in low gear all the time on a tractor, this is what happens when a tire locks up. Not abuse.

I find it difficult to form much of an opinion on matter but I really can't imagine that I could have a problem like this and have a skid for this duration. For most operators that are paying attention I think you would have stopped the machine long before it was dragged sideways this far.

 

[RoyJackson]

Aluminum has a far lower fatigue life than steel. However if you are well below the endurance limit of the material, the fatigue life should be near infinite.... or at least beyond the life of the rest of the machine.

So the question is... are the parts exposed to stress above the endurance limit? And for how long.

I'm not a metallurgist (my field is Quality Assurance/Engineering), but I think you're simplifying things a bit too much for that blanket statement. Fatigue strength depends on the alloy and, more importantly, the design.
If there had been a trend in failures of this design and material, you'd have a point...but to the best of my knowledge, there hasn't been a lot of failures (more then likely, we would have read about it on TBN).

BTW, I think most ferrous castings on tractors are cast iron, not cast steel.

 

[AKfish]

I didn't notice the gouges on the tire lugs... I believe the collective minds have determined the most likely reason for the axle housing failure as well.

That said, I have to ask - how many owner's would have continued to use their equipment when they recognized the implement was damaging the tractor's tires?

I'd like to see the lower link arms, too. It wouldn't be too much of a stretch to believe that the inside and outside of the link arms are likely damaged from contact with the tires and the bottom of the axle housing.

I also recognize that Deere has adopted new style 3pt. link arms and replaced them on folk's tractors after purchase to avoid similar problems with attachments striking the rear tires.

IMHO - there was a "failure-of-common-sense" by the operator to recognize a serious problem and secondarily; a poor equipment design from JD with the 3pt draft links.

Best of both world solution would be for Deere and the owner to split the costs of repair and labor - 50/50.

AKfish

 

[higgy]

I would think with a breakdown record like that, he will be very lucky to get JD to chip in. I was not there and did not see the event, however, we are operators of equipment not passengers on equipment.

 

[pilot-werx]

Holy.... Talk about meeting the judges, juries, and executioners all in one thread.... Without seeing it firsthand who the heck knows what happened..

Being both a pilot and mechanical engineer, It is hard to point a finger when you are simply looking at pictures.....