440CT Series 3 has broken pin on bucket curl 3 times in six months. Any ideas?

[Rick 4seasons]

We have a 440CT. Moderate work so nothing extreme. We grease religiously and yet the same pin has snapped in the middle three times over the last six months. Yesterday was dumping a quarter bucket of gravel out when pin broke. No stress at all at the time just dumping the bucket. Onlyrics thing I noticed is that when pin broke the bucket curled much faster with only one ram. The ram still attached would extend all the way before the other would even begin moving. When both are extended the not attached one would retract all the way before the other would even move. This just may be a coincidence. But this time when the pin broke it ended up bending the coupler frame and breaking most of the way through. Any ideas on why this is how?

 

[walio123]

There may be several reasons. Bad geometry of the coupling frame, too soft or too hard pins. If you put original and not made pins, verify the geometry of the coupling frame. The distance between the arm pins and cylinder pins must be the same on both sides.Diagonals between the left arm pin and right cylinder pin must be the same as the distance between the right arm pin and left cylinder pin.If there is a difference in these distances is obtained it leads to wedging and breaking of pins at his weakest point- this is usually a middle hole- where goes grease.As for the cylinders - it is normal to react that way.