Dropping a rudder is pretty straight forward. Start at the top and start removing things on the rudder post until the rudder falls out.
The squeak may be the result of worn rudder bearings. Grab the rudder and shake it, it should not wiggle. If it does you need new rudder bearings. If it is solid, then proceed, bearing in mind adding a delrin ring may affect the alignment of the steering system. Take photos along the way to remember where every thing goes.
I'm assuming you have an Edson Wheel. First step is to ensure there is enough room under the rudder to lower sufficiently to accomplish what you want to do. If not, get a shovel and start digging or you will need the travel lift.
Next, support the rudder from dropping in a manner that allow it to be lowered when it is time. I've used blocking and a small floor jack.
The hardest part will be removing the steering quadrant. The Edson quadrants are split and clamp around the rudder post with an additional through bolt. Other than access the mix of SS and aluminum is a recipe for corrosion which may make the job more difficult. You may also need to remove the steering cables, which are attached to eyebolts and double nutted. Now is also a good time to service the steering system which has not been done in a really long time. Check the cables, idler pulleys and the chain for wear, pay close attention to the cable as it can develop fish hooks and need replacing. There is good information on the Edson Marine website for servicing the steering system.
There may be some spacers, thrust washers, or support collars under the quadrant. At the top of the rudder shaft there should be some sort of seal if the top is below the water line, if above the water line, probably not. Again, it should be pretty obvious what needs to be removed. Some builders used a gland similar to the stuffing box on the prop shaft, there will be on row of packing material beneath the cover. Replace the packing while you're there. Beneath the gland will be the upper rudder bearing. Once the gland packing is removed the rudder should slide out.
