I just bought a set of new window rollers for my '67 SS and after they came, I noticed on the old ones that the stem that attaches to the raise/lower assembly is kind of 'smashed' in to the arm. It almost has a star shape to the back side. The new parts just have a stem that will fit thru the hole, but the question I have is, How do I 'smash' the new posts into the arm so that it will stay, and given that I will have to have the plastic roller in place when I do this, how do I protect it from damage?