Check keel pin as well as bolts
The 4 bolts that hold the keel in are easy to change. They simply screw thru the brass pivot points into blind nuts it the hull. I checked mine and they appeared ok, but were loose. What you should really be worried about the the brass pivot pin that the keel swings on. Mine was worn 1/2 way through. I ordered new parts from Catalina Direct (keel pin and pivot bushing) and redid mine. Not a hard job at all.