Leaf spring nut. Left.rear. PartQualifier: rear. Right.rear. A solid metal or plastic block with a threaded hole in the center which is used to tighten or adjust the Suspension Leaf Spring. Leaf Spring Shackle Nut. Part cannot be reused/reinstalled. Suspension Control Arm Nut. Suspension Trailing Arm Nut. Ft cntl lock. Leaf Spring Shackle. Suspension Control. Trailing. U - bolt.