I'm getting ready to fix the window regulators from my 71 charger. I ordered the replacement sliders for the ones broken/missing from mine, but I'm not entirely certain how to go about replacing them. I was expecting new plastic to snap into place but the new ones actually incorporate the metal ball which they are install into the regulator arm. I'm wondering the proper way to remove the old one/install the new ones. It looks like the original ones are pressed into place but I don't want to assume and wind up mangling the regulator in the process. Anyone out there have some insight into this?

Since I didn't receive a response I made a educated guess at accomplishing this and it seems to have turned out as hoped. Here's what I did in case someone down the line has the same question and finds this in a search.

The metal part wasn't pressed in so much as the back part essentially acted as a rivet. First I ground down the flattened area on the back side and pulled it out with vice grips, then I got a solid piece of iron to act as an anvil, and my 8 lb sledge. I then placed the ball under the arm so the small "rivet" part is sticking up through the arm, a few relatively moderate swings of the sledge and it was secure. The metal ball the slider is on has a flat part which sticks out far enough against the anvil that you won't break the plastic in this process. I did use some scrap wood to make sure the regulator arm was approximately parallel to the anvil before I secured the slider ball to it. All told it only took a few minutes per slider to replace, it took me longer to make this post than replace all 3 on the regulator in question.

Looked at lot harder then it was...
I wondered if you could have "popped" the plastic piece off snapped it on the old metal ball?

I'm pretty sure there's a high likelihood of breaking the plastic if you try to do that.