Futaba FU1K37601 First Gear for BLS351 Servos  [FU1K37601]

First-stage gear service for BLS351 units

This replacement first gear is offered as a field-service component for Futaba BLS351 servos installed in radio-controlled models, intended to reestablish correct gear engagement when the initial first-stage gear is worn or damaged. It functions as a maintenance spare to keep servo output reliable.

To fit the gear, remove the servo shell, extract the gear stack and interchange the first gear while maintaining bearing and spacer order. Reassemble with care, ensure the output spline and servo horn line up, and test for free rotation before applying power to prevent binding.

When tuning, the first-stage gear affects mesh and backlash; installing a new first gear can reduce play and deliver more consistent servo response for steering and control surfaces. After replacement, set neutral and perform several low-load cycles to confirm smooth behaviour.