Out of there!
Next, clean the housings. Pay close attention to the areas where the o-rings slide in and seat. These areas must be free of all dirt, pitting, and damage. The roller bearing must be blown dry with air and immediately oiled before placing the cleaned housings in a clean place.
On the rear housing, the compensating valve bore may be corroded like this.
Use a tube brush, then a tube brush wrapped in Scotch-Brite to clean this bore.
Place the new green o-rings on the barrel,lube them with silicone paste. Then install the thrust bearing and front housing.
Housing should push on by hand. If not, the dowel pin may not be lined up.