How to: Replace a Servo

The steering servo in your RC car is the electric motor that moves the steering side to side. In the same way that you need good gear mesh and throttle calibration to go fast in a straight line, you need your steering system to be in top form to carve up the corners.

In nitro and 2-stroke powered RC, servos can also control brake linkages and carburetors, and gearboxes in crawlers, among other things. Most modern hobby-grade servos have standardized fitment, consisting of 4 screws/bolts that anchor the servo to a mount on the chassis. The servo also has an arm or “horn” that connects to the rest of the steering to make corners possible. This is held on by a single screw and needs to be removed when changing servos as well.

Every model will differ slightly in how the servo is removed, but it is the reattaching of the servo arm in the correct spot that is the real trick.

Once the new servo is in the car, turn the hand controller on and make sure the steering trim is set to neutral.

Steering Trim Note: Many ready to run (RTR) RC Cars come with a FlySky GT-2 variant controller. On these, the throttle trim dial is the one on the left. To set this steering trim dial to 0, the little notch should be pointing to the left, or 9 o’clock.

Now turn on the car. The servo will reset itself to centre, and with the steering pointing straight, you can go ahead and screw on the servo arm/horn.

This ensures the car will run straight and true and have a full range of steering in both directions.

Without allowing the steering servo to self-centre, it will likely pull hard to one side when the car is switched on. At best, this is both frustrating and embarrassing, especially if you have just been demonstrating your mechanical genius. At worst, the servo can pull so hard past the normal steering range that it will strip one of its gears or burn out. This is frustrating and embarrassing too, but now you’re down a brand new servo as well.

By simply switching the car on and letting the steering centre itself, it can now be fine-tuned with that same steering trim dial for a perfectly straight drive.

…And that’s way better for breaking speed records.