live2plant
Member
Good Afternoon to all. I am going from eight on up to a full set of 20 front end weights on a 4640. I had the shorter bracket for up to 12 and so am installing the longer one for up to the 20 I need. The shorter bracket had 6.5 inch bolts going all the way through front and rear cast but this long bracket attaches only from the back cast so shorter bolts. John Deere says 2 inch long bolts but they also say a washer that is 1/4 inch thick added to the one inch back cast of bracket to penetrate only leaving 3/4 inch into recipient threads. That's four 3/4 inch grade 8 bolts penetrating only 3/4 inch in threads to hold a full ton plus weight bar. I measured carefully not wanting to bottom the bolts out in the hole and there is easily enough additional threads inside and depth to accommodate 3 inch long bolts and not bottom them out before torque is achieved at the heads so I went with 3 inch bolts. I am also adding lock washers not required as per JD with their required thick flat washers. I would have loved to have seen a lip in the bracket cast to go over the front end cast and hold that weight but it is all straight down on the bolts. So now we are looking at 1 3/4 inch of thread on four bolts holding it all. I need to feel secure and wonder of other's experiences with the same or something similar. I cannot say that I have ever known of a weight bar loaded to actually fail but this is a bunch of weight. I am seeing by chart the required torque for 3/4 inch grade 8 bolts at 510 ft. lbs. Is that much really necessary and would it put the softer than hard bolt threads inside at risk along with over stressing the bolts and I wonder about using red thread lock as well. Many thanks, Greg
