I have a JD 310A Backhoe and I want to change the rear hoe bucket to a smaller narrower bucket. I find the bucket is held on the boom by 6-8 large heavy duty cotter pins. The pins are about 4-5 inches long and maybe 1/4 to 3/8 of an inch thick and the fit into the holes in the pins to hold everything together. My question is, are these cotter pins normally used for this purpose or are they bootlegged by the previous owner? I cannot find new replacement pins on any JD parts website and wonder is there something else I should use? My parts book does show cotter pins but the part # does not show anyplace I have looked. Looking for a place I can order 6-8 of these large thick cotter pins. Thanks in advance....