Land Rover Repair: ABS light, wheel bearing grease, swivel pins

Question
I recently worked the swivel pin preload on my 1998 Disco.
Brakes seem to be working fine, but I noticed on the way to work, my ABS light came on.
When I stopped, shut the truck off, restarted and pulled away, it went out at about 6MPH as usual. Too soon to say when/if it comes back on.
I am assuming I either damaged one of the sensors when I pulled the swivel pins, or I should not have put wheel bearing grease on when I reinstalled them.
Prior to this I had no ABS light issues.

Answer
The reluctor ring on the axle and the abs sensor itself need to be clean and grease free.  Other than that, there is no trick to installing them.  They should not be damaged by removal and refit but you may not have them seated all the way.  Try tapping them down once you make sure they are clean