I bought a 2010 KX121-3 on Valentine's Day with 818 hours on it. I broke the first pin at 853 hours (4/1/13) and broke the next today at 963. That's 110 hours on a $200 pin. Both pins broke at the grease hole at the center of the pin. No other damage, there is some wear to the bushings, I have replacements already (condition of purchase, new pins/bushings for the bucket and linkage). The ex has the Kubota quick coupler and thumb. On the thumb I have added a small "tooth" to each tine of the thumb.
The work I'm doing mainly is grubbing/clearing/digging out stumps. While the work can support the additional overhead, I would prefer to not have the problem reoccur. It broke 2 hours into an 8-9 hour day with no rental ex available. Also the dealer doesn't stock that part.
What can I do to minimize the risk of breakage? Obviously grabbing things eccentrically puts a good moment load on the pin. I wonder if bushing wear would increase the loading on the pin. I also figure my teeth on the thumb increase loading over the stock thumb, however it makes grabbing wood far easier and thus is a requirement. For some duties I could swap over to a hanging grapple, which would reduce the loading on the pin while handling debris.
Lastly, I suppose I shouldn't expect any warranty on the 2 month old pin, eh?
The work I'm doing mainly is grubbing/clearing/digging out stumps. While the work can support the additional overhead, I would prefer to not have the problem reoccur. It broke 2 hours into an 8-9 hour day with no rental ex available. Also the dealer doesn't stock that part.
What can I do to minimize the risk of breakage? Obviously grabbing things eccentrically puts a good moment load on the pin. I wonder if bushing wear would increase the loading on the pin. I also figure my teeth on the thumb increase loading over the stock thumb, however it makes grabbing wood far easier and thus is a requirement. For some duties I could swap over to a hanging grapple, which would reduce the loading on the pin while handling debris.
Lastly, I suppose I shouldn't expect any warranty on the 2 month old pin, eh?