I've fought with slide bolts..... Had one instance where the bolt actually twisted.... The bolts have grooves in them and it was very noticable. 6 point socket, a vice and heat. Don't use a 12 point socket/wrench/open end wrench on brake bolts unless it's a fresh redo.

The piece between the two pads...anti-rattle clip?

If you did a 12" upgrade and used junkyard parts the issue could be the pins and rubber bushing inside. Let me explain. I got the brackets for my 12" upgrade from a 01 Impala. My 03 GP slider bolts would not go in the calipers. I went back to the impala and looked at the slider bolts and they really tapered at the end. Inside the caliper is a 1.5" or so rubber bushing that the slider bolt goes into. I used a long wood screw and pulled the bushings out and used my 03 bolts. I first used the impala bolts, but the calipers moved around too much for my taste.

Impala Bolts:



Grand Prix Bolts: (top bolt)

Top pic isn't working, at least for me. Can you elaborate a little more on what you mean chevman? Are you talking about using your stock calipers with the upgraded bracket in order to use 12" rotors? I've got the upgraded calipers too (dual piston).

The top pic is from the clubgp 12" upgrade thread. Yes, I'm talking stock calipers with 12" upgrade.

7th pic of this thread in the actual instruction section.. It has a red hammer in the picture.
http://www.clubgp.com/cgi-asp/mods.asp?modid=3

I know ZZP just listed the latest parts for the conversion on their site.