Check that any parts you are not going to replace are undamaged before ordering replacements.
Remove protective grease or other material from new parts. Compare them with the old ones to find which is left and which is right. Trying to screw on the wrong joint would damage both joint and rod.
To refit a ball joint to a track rod, grease the thread and screw the joint into place, giving it exactly the same number of turns as when the old joint was removed. Or screw it up to a mark you made earlier.
Do not tighten the locknut yet. Make sure the ball-joint stud is pointing straight up (or down, as appropriate) when in the middle of its travel, as the joint is flexed.
If not, twist the whole joint on the rod to bring the stud into line. Push the stud carefully through the bore in the steering arm.
Fit the washer and locking nut to the stud, and tighten the nut to pull the tapered stud into the bore.
If a self-locking nut was used, replace it with a new one: a self-locking nut should not be used twice.
If the threads are stiff, the nut may make the stud turn so that it does not screw up.
Hold the stud by levering against the other side of the joint with a bar resting on the inside wheel rim.
Finish tightening the nut with a torque wrench set to the correct loading. If you cannot obtain the correct setting from a service manual or your local dealer, 25 lb ft (3.5 kg m) is about right.
If a castellated locknut is used, tighten it more, not less, to align one of its cut-outs with the hole for the split pin. Always use a new split pin. Insert it, prise it apart with a small screwdriver and bend the two halves opposite ways around the nut.
Tighten a ball-joint locknut while you hold the ball joint firmly with a spanner or self-locking grips to stop it from turning. Otherwise the joint will be damaged.
Check that the toe-in or toe-out of the wheels is correct (See Adjusting toe alignment on wheels). The setting is usually given in the car handbook. This check should be done by a garage if you do not have the equipment for it.