Straight forward, use a suitable size drift & tap away, after removing pich bolts!
Keep old plunger top screws even if fitting new ones.
Use the old ones to drive the column back in without damaging the thread
Note orientation of the groove in the rod which engages with a locating bolt it is important for re assembly
Pack everything with loads of grease then some more for reassembly.
See seperate threads re: putting it all back
