So I bought a dual steering stabilizer kit fr rancho and one of the brackets mounts to the driver side leaf spring u-bolt. The nuts in the kit are for 5/8"-18 but they slide right over the top of the threads (too big). I figured I'd go to the part store and pick up different nuts but 1) I can't figure out the size/thread pitch of the u-bolt and 2) I guessed a size smaller 9/16-18 and that doesn't work. Is it metric?