Hi Bob,
I need to work on mine too, but other priorities for now. However, I did find these great instruction papers for telescopic column rebuild which also provides instructions for replacing the turn signal switch. These papers are for 67 and 68. Not sure what year your car is, but even if its a later C3, this should be a good guide for you. You can also google 'Jim Shea Corvette steering' to see is he has more instructions for later C3s.
Good Luck
Luke