Internal Gear Train for BLS252 FUAS4155 Compatible with Futaba  [FUAS4155]

Internal Gear Replacement Overview

This Futaba FUAS4155 gear set functions as the internal replacement gear train for BLS252-class servos in electric RC hobby applications. The service references AS4155 and EBS3362 correspond to this gear kit and assist identification against the original BLS252 components.

Fit this set when gear wear causes backlash, clicking, or loss of fine positional control. Renewing the gear train can significantly improve repeatability and reduce intermittent control feel during tuning sessions.

Disassemble the servo carefully and preserve the gear stacking order and any spacers or shims. After installation, confirm full travel and neutral alignment prior to refitting the servo into its mounting to prevent binding or misalignment.

When servicing BLS252 servos, this Futaba-designated gear set supplies the correct part numbers to replace the internal gears and restore consistent operation.