Applies to vehicles: with removable towing bracket
Make sure the ball joint is clean and undamaged.
Check the shaft section Fig. 1 -3-, release catch -4- and knob -5- on the ball joint to make sure they are clean and undamaged.
The spring mechanism inside the ball joint must be in the "ready" position.
Check that the red marking Fig. 2 -6- on the knob is inside the green zone on the ball joint.
Check that the retaining balls -7- are inside the holes in the shaft section of the ball joint.
Check that the knob protrudes visibly from the ball joint, so that there is a clear gap -8- between the knob and the ball joint.
The ball joint can only be installed if the internal spring mechanism is in the ready position.
Continued Link.