Caliper brake -- middle piece loose I am putting my old cane creek 200 sl brakes on a different bike. I've had these brakes sitting around for awhile and I don't recall any problems the last time I had them on a bike. 

But, on this new bike, the full calipers themselves loose, both front and back brakes, and has a wobble to it. I'm not getting great braking power and suspect this is why. 

Could these brakes be the wrong size for the frame? It's an older Legnano steel road  (pretty similar to the 80s bianchi style road frames), and I am not sure how to figure the compatibility.
Some brake calipers have a small locking screw with which you can adjust the rotation of the brake caliper without having too loosen the bolt with which the caliper is mounted to the frame. Check if your caliper has such a locking screw and if tightening it helps. It should be approx 2mm in diameter.

The afore mentioned locking screw can be seen here: https://www.parktool.com/assets/img/repairhelp/dual27.jpg

Image source: https://www.parktool.com/blog/repair-help/dual-pivot-brake-service