Contains 2 park tool chain tool pins.
Replacement:
1/ Remove plunger completely from tool
2/ Unthread old pin from plunger using a 9/32" 12-point box end spanner (or pliers). If using pliers use cre not to damage threads of plunger.
3/ Grease replacement pin threads, install and tighten
4/ Grease threads of plunger and install into tool
Park Tool reference: CTP