Iflg Defender manual UDEN pakning monteret:
To check the top swivel pin pre-load attach a spring
balance to the track-rod ball joint bore and pull the
balance to determine the effort required to turn the
swivel. The resistance, once the initial inertia has
been overcome, should be 3,60 to 430 Kg (8 to
10 Ibs). If necessary, adjust by removing or adding
shims to the top swivel pin as required.
http://www.landroverweb.com/Pdf-files/Manuals/Defender-90-110-workshop-manual-4.pdf