The piece that is replaced is the sliding foot that goes on the end of the regulator arm.
The regulator must be removed from the door. The old rivet will be still in the arm. The plastic will be broken from it. The peened portion of the rivet must be ground off, then the body driven out with a punch. The new piece will add much to the understanding of whats next.
The rivet is built into the plastic foot loosely and the head of the rivet is recessed into the foot. I place a 3/8inch punch vertically into a vise. I then place the foot over the punch with the head of the rivet setting on the flat head of the punch. The small end of the rivet will be facing upward. Place the hole in the regulator arm over the rivet till the rivet protrudes. This whole arrangement is now held steady by firm pressure downward with the arm against the hard punch face. Use a ball peen hammer to mushroom the end of the rivet till it is secure.
Replace the regulator.
Bosch Master, ASE Master, L1
33 years MB technician