We have an '88 Catalina 30 and also had exactly that same problem. The steering was very stiff. Tried everything including lubing all the cables, chain, pulleys in the pedestal, adjusting cable tension, etc. None of that worked. Then, we read an article in Mainsheet (Catalina mag) in which someone found the cause and fix. A previous owner had lubed the rudder post with some sort of grease. Over the years it had hardened into a sort of tar-like substance. We dropped the rudder out of the boat when it was hauled to do the bottom and cleaned the tar-like stuff out of the rudder tube and off the rudder post with a stiff brush and acetone. Next we applied a VERY THIN layer of teflon lube and put the rudder back into its tube, reattached everything, and tensioned the cables. Problem solved. You may very well have the same issue. It's easy enough to drop the rudder when your boat is out of the water. Just disconnect the steering cables, remove the bolt holding the steering radial (not really a quadrant) and the rudder can be dropped out. It does NOT require digging a hole for the rudder or having the boat propped up extra high or anything like that, assuming you have the regular fin keel. There is no packing nut, packing gland or any such thing on the rudder of a 1988 Catalina 30. The rudder post is simply in a fiberglass tube. If any questions contact me via the owner's directory on this site.
Gary Kunkel