Futaba S3155 Internal Gear Set Replacement - FUAS4140  [FUAS4140]

Direct Replacement Gearset for S3155 Servo

This Futaba FUAS4140 gear set is supplied as a replacement for the S3155 servo to restore internal gear action when teeth wear or slip, helping return the unit to reliable operation.

Compatibility: designed specifically for the Futaba S3155 servo; do not assume fitment to other models without checking official manufacturer references.

Installation role: swapping worn internal gears can recover positional precision and reduce play at the output. Typical service involves opening the servo case, exchanging the gear train components, reassembling, and confirming neutral position and travel. After fitting, set endpoint limits and run a basic function check to confirm smooth rotation and correct centering.

Tuning implications: gears do not change electrical response, but damaged teeth introduce backlash and inconsistent feedback to the controller; fresh gears help maintain precise steering and throttle control in scale RC applications.