I had to take my a-pillar off and when I went to tap out the plastic rivets, the larger piece came out of the door frame so now I have nothing to put a rivet through. What do I need to replace it?

 

The rivets are a one time use item. You need to buy new rivets and put them back in when you re-install the trim.

 

I got that, was going to try and use regular metal ones realizing that might not work but my question is what the larger piece is that the rivet goes into. Now I only have a large round whole in the door frame about the size of a quarter.

 

I think you will have to include a picture. From what I remember I thought the rivet went into the metal of the A pillar.

 

It is just the rivet, I looked them up. I thought the hole was too large for just the rivet to fill but now that I am looking at it, I think it does.

 

It may help future folks reading this thread if you were using the correct part names...you're referring to having removed the windshield trim/finisher that goes over the outside of the a-pillar, not the A-Pillar itself. (The Windshield Finisher you are referencing can be found here: Windshield Pillar Finisher Right Side (Genuine Part # DCB500060PMA))

...according to AB, this is what you should be using to secure them to the actual A-Pillar.: Rivet - Nylon Sill Finisher (Part # 79086) and Clip Windshield Finisher 3 Per Side (Genuine Part # AWR4426)

 

Yes you are right.