Futaba FUAS4138 Servo Case Set for S3115 S3116  [FUAS4138]

Servo case for S3115/S3116

This Futaba FUAS4138 servo case set is a direct replacement housing for Futaba S3115 and S3116 servos, supplied without retail packing. The article focuses on fitment and service use for hobby-grade RC servos rather than performance claims.

Compatibility is limited to the S3115 and S3116 servo models named above; do not assume fitment for other Futaba models without verification. Use this case to replace damaged or worn housings, restore correct alignment of internal components, and secure the gear stack and PCB during routine maintenance.

Installation notes: remove the servo horn and outer shell, document gear and PCB orientation, transfer internal components into the replacement case while observing clearance and screw torque, then reassemble and check end-to-end travel and centering on your transmitter before use. If metal shims or bearings are present in the original unit, retain their positions when reassembling to preserve gear alignment.

Tuning and service role: this case is intended to support reliable reassembly after repairs and to maintain mechanical alignment that affects smooth operation and consistent feedback from the servo. It is not a performance upgrade on its own but a maintenance item to keep S3115/S3116 servos operating as designed.