According to Warren Pandy, Catalina, the upper bearings are ‘MARELON’, by Forespar. Therefore, I assume, that the lower ones are of the same material.
Whilst my experiences have only been with the upper bearings and may not give you answers on your current problem, you may be interested in Warren’s recommendations (which proved to be excellent and provided the solutions).
1. When I had some groaning and rumbling in the upper part of the rudder in high seas, he gave the following advice:
[
INDENT]“Make sure the 4 or 5 bolts that secure the upper Marelon* bearing to the deck are not loose or the holes in the deck "ovaled" out some. If so, let me know what you find, it's an easy correction.”[/INDENT]
I just had to tighten the bolts.
2. About 2-3 months ago I finally managed to seal the cockpit lid on the steering box, finally drying the latter. Subsequently, when we had a very dry spell with temperatures close to 40C, I had the dry groaning noise back and no tightening of bolts helped.
Warren made the correct deduction and suggested to moisten the bearing:
“The answer may be that the steering well or "box" used to be wet but is now dry. Forespar only recommends water as the only "lubricant" needed or required for the MARELON* (white special high strength "plastic" bearings) If a petroleum based grease is ever used on them it will cause the surface to swell or expand and then the bearing could be tight on the shaft, depending on the prior clearance. (they start with a minimum of .010" clearance) Try water spray or misting that well again and see if the groan goes away. Have heard of some yards that unknowingly put an oil based grease on these bearings and before long the shaft was so tight the owner had a tough time turning the wheel.
It worked.