I don't know if this still applies to the modern sedan chairs, but on my old 4/4 there were going two bolts through the wood with nuts and the third was a wood screw. To stop the bolts eating through the wood with wobbliness as a result I fabricated a steel strip which runs the lenght of both hinges with holes for the bolts instead of the washers. The wood screw(s) was changed to nut and bolt. This of course was done on the car AND the door(s). Since then (40 years ago) I never had wobbly doors and the hinges are still the first - despite not beeing oiled sometimes for several years (the oil can is always out of reach when the thought arises that they could be in need).
Frank
