C4 Maintenance 10. Joint #6140 C Series Maintenance Manual Rev.210.2 Joint #6 - Replacing the Reduction Gear UnitRemoval: Joint #6 Reduction gear unit1. Turn OFF the Controller power.2. Remove the Arm #4 side cover.For details, refer to C4 Maintenance: 3. Covers.3. Remove the Joint #5 motor unit and the reduction gear unit.For details, refer to C4 Maintenance: 9.2 Joint #5 – Replacing the Motor, Installation steps (3) through(11).4. Remove the O-ring on the installation surface of the Arm #4 and #5.The O-ring of the Arm #4 is on the Arm #4 plate which was removedin the step (4).For the O-ring of the Arm #5, see the photo on the right.The O-ring will be used again. Be careful not to lose it. O-ring5. Remove the Joint #6 flange.Hexagon socket head cap bolts: 7-M3×6Name Quantity NoteMaintenanceParts Joint #6 reduction gear unit 1 1539261ToolsHexagonalwrenchwidth across flats: 1.5 mm 1 For M3 hexagon socket set screwsFor M2 hexagon socket head cap boltswidth across flats: 2 mm 1 For M2.5 hexagon socket head cap boltswidth across flats: 2.5 mm 1 For M3 hexagon socket head cap boltswidth across flats: 3 mm 1 For M4 hexagon socket head cap boltsCross-point screwdriver 1 For coversWrench width 5.5 1width 8 1Force gauge 1 For belt tension adjustment