IF you are confident that the coil is OK, then go to Bunnings (or similar) and get a reamer of the right size.  Use this to get a bit more room in the coil and put a new sleeve in.  A quick and dirty is to clean inside the coil as best you can, coat the inside with silicon spray and whack the coil sleeve in with a sharp tap from a block of wood or similar.

cheers
Ian