Futaba FUAS4118 Replacement Internal Gear Group for S9154  [FUAS4118]

Replacement Internal Gear Set for S9154

This RC-scale servo accessory acts as the internal gear set for Futaba S9154 servos, sold under the model code FUAS4118. It is supplied to replace worn or damaged internal drive gears and is not a whole servo assembly.

The component is focused on maintenance: renew worn gears, check gear engagement and play, and return the unit to predictable mechanical behaviour. Perform the swap on a clean bench and keep small parts like bearings and shims organised to match original clearances during reassembly.

Installation overview: remove the servo cover and motor fixing screws, document the original gear sequence, lift the gear train free, install FUAS4118 gears and reassemble in reverse order. Once reassembled confirm free rotation, accurate centring and a secure servo horn before refitting to the airframe or model. Adjust mesh and run bench checks to verify control response.

For tuning and setup, fitting new internal gears can eliminate play from worn teeth and recover repeatable control action. After installation re-confirm endpoint settings and centring while the servo is under normal load to ensure stable behaviour in operation.