Putting my ome rear springs on. the nut for the locating pin doesn't fit the hole in the center of the plate the u-bolts go through. So I am guessing the nut comes off plate goes on then nut back on? there is no washer on the nut now should I put one on? The old stuff was so rusted I had to use a grinder and bfh to get it all apart and didn't pay attention well enough I guess. thanks.