This repair pertains to twin engined Marinettes, but the single screw models are similar. On my 1985, the port rudder was very sloppy in the bearings after 20 years of use. The starboard side—that doesn’t do as much work (the linkage comes in on the port side)—was in good shape. New bushings are available from Marinette Yachts, and they MUST be non-metallic.
The first step is to remove all the linkages and stuffing boxes, after which the rudders should drop right down with a minor push. The boat needs to be elevated enough for the rudder AND the post to come out, so if you’re planning to do this, be sure to have the boat blocked nice and high. That means the height of the rudder PLUS the length of the shaft inside the boat.
Removing the old bushing was a royal pain until I learned about a “magic” bushing removal tool, which is pictured in the “Tools“ photo: a lathe chisel that is sharpened backwards (so it cuts from the outside). It does a great job of getting the remains of the bushing out of there. (I also used it for removing the prop shaft bushing someone had epoxied in.) The first step to removing the bushing is to saber saw through the rubber and bakelite material for the length of the bushing (about 3 inches). Make this cut in several locations about the bushing—say, every 45 degrees. With luck the bushing will disintegrate and, with a little help from the “magic” tool, the rest will come right out.
Next comes cleaning the inside of the pipe, so the new bushing will go in without hanging up. I used a one inch drum sander for this task, complete with an extension shaft to get way down inside the pipe. The “Go gage” show in the “Tools” photo is used to ensure there are no obstructions left to hang the bushing up. The OD of the gage is just under what the pipe ID should be, so if it goes through okay, the bushing will fit nicely. Finally, one of the bushings had so corroded the aluminum pipe that the bushing was too loose, so I applied some PC-7 marine epoxy (Ace or True Value Hardware) to keep it in place.
Note: All of the tools shown in the photo are available, free of charge, to anyone doing this repair. Just pay the shipping costs, both ways.
Tools used in repair:
Port Rudder Linkage:
Another view:
Crack in Rudder Tie Bar:
Stuffing Box Assembly:
Port Rudder Bushing in Place:
Port Rudder Linkage in Place:
Starboard Rudder Linkage in Place:
replace with bronze packing boxes (stuffing box) similar to the type used on the propeller shafts 
