I agree with much posted.
verify all is well with the kingpins, shackles, tie rods and steering. Once your sure there is nothing worn, then lubricate.
Bump steer is simply a change in geometry when imparting a vertical displacement to one of the front wheels. If your suspension is in proper working order, the vehicle will track true. Bump steer happens with any suspension design if there is allowance by poor geometry or worn parts.
New suspensions are "lubed for life". Older suspensions need routine maintenance. They called them lube services for a reason, not just an oil change.
