Remove the end cover by undoing the three fixing screws using a Posi screwdriver
Remove the two screws fixing the lift arm to the main cutter bar using an 8mm spanner (wrench)
Remove the hinge screw using a 4mm Allen (hex) key, clean the plastic bush and washer with a dry cloth, do not use solvents. There may be white PTFE (plumbers) tape around the hinge screw leave this in place or replace if in bad condition. Wind enough on so plastic bush is a tight fit on the screw.