For what part? lower ball joint? or the caliper bracket? Because if it's the caliper bracket mount on the spindle the caliper bracket may not be located properly, which could contribute to the clearance issues you're having on the center.
Regardless, modifying brand new parts is rarely the way to go. If the parts have an issue, returning them for a replacement is the better way to go. Once they're modified no one will take them back, and you're stuck with a poorly manufactured part.
