Inspecting kingpins

[bwake]

Inspection of the upper and lower bushings and thrust bearing are all done with a dial indicator as previously stated. Generally, specs of .015 lateral movement or less are considered ok to run. If either of the bushings are over this, everything should be replaced as a set. Vertical movement should be no more than .040, if it's more than that, the lower thrust bearing is worn or there were not enough shims put in when it was originally done.
One thing many people overlook is excessive wear of or loose wheel bearings. When checking the kingpins, apply the brakes to remove the possibility of feeling the loose bearings. The movement that you are talking about could possibly be a loose bearing and not have anything to do with the kingpins.
If you do have to replace the kingpin and bushings, make sure that the axle eye is checked for wear before going back with the new set. If there is wear in the axle eye, someone with the right equipment can ream it and install a bushing there as well.