There are 4 pins that connect the tower head to the turntable. Near these pins there are 4 bolts that apply torsional pressure against the pins. The Operator Manual says to tighten the bolts then back them off 1/4 turn and set the jam nut. Blake Smith from Potain recommends these bolt be tightened and not backed off. Throughout operation of the crane occasionally re-tighten these bolts. The pin connections will pop as has they “seat in” during operation and will eventually quiet. This is a common issue with new 389 cranes.
