Strip, clean and inspect headset and bearings. Refit or replace bearings as required. 

Installation of new headset unit including bearings, crown race and bearing cups.

In rare circumstances it is necessary to prepare the head tube before a new headset can be installed. Typically this is after a frame has been repainted or when the bike is experiencing repeated premature headset failure due to misaligned cups.

All  press-fit bottom brackets, including those with with replaceable sealed bearings. Remove crank, inspect, service then re-fit/replace bottom bracket  or bearings. Re-install crank.  

Facing & reaming  head tube to remove excess paint or frame material to ensure headset fits in alignment with the frame.