Futaba FU1K26101 Metal First Gear for S9152 and S9153 Servos  [FU1K26101]

Servo input-stage gear detail

The Futaba FU1K26101 first gear is an RC-scale replacement part made for Futaba S9152 and S9153 servos. It is supplied without retail packing, as stated in the listing. Serving as the input-stage gear, it transfers rotational motion from the motor pinion into the gearbox and plays a key role in steering response and control fidelity for scale vehicles.

Installation notes: remove the horn and case screws, carefully lift out the internals and mark the gear stack order before extracting the first gear. Check mating surfaces and bearings for damage or burrs, then fit the new gear with correct axial alignment and a light, consistent gear mesh. Reassemble the servo and confirm smooth free rotation before refitting in the model.

Tuning and maintenance role: installing a new first gear can reduce endplay and uneven centring, helping return consistent control. While servicing, remove debris, renew old grease if necessary, and run the servo through full travel to ensure there is no binding after installation.