Try spraying a light coat of paint or if you get some Dykem blueing, cover the ball seal and assemble with the proper torque. Remove the ball and look for an uneven contact surface around the ball on both sides. If you have a high spot somewhere, you can take it down and re-test. Clean the fasteners of rust and torque dry. Too much torque will pull the studs out of the casting. Look for evidence of that happpening already.