By having a (spurious) SE&CR body, the loco appears to be the current R30039. If that is so, Service Sheet 139 is not relevant, indeed misleading. You would be better served referring to sheet 348. Screw S1014 has a BA thread so it has cut its way in to the wheel where a metric-threaded screw once sat. For China-made models, the screws are supplied only with the rods.