How to Align Servos on Dual Servo RC Trucks

Learn the proper procedure to adjust a dual-servo setup

It’s a familiar story: mailboxes jump out of nowhere and curbs appear overnight to catch RC drivers unaware. If you’ve ever experienced these or other road hazards you know that a strong hit could damage your steering servo. Replacing a single servo is a pretty straightforward job, but what about RC trucks with dual servos? This article discusses the importance of proper alignment when working on dual-servo RC vehicles and how to adjust them.

This article assumes you are replacing at least one servo, but it’s always a good idea to check your servo alignment from time to time. If your servos make a constant buzzing sound or get warm without any steering input, that’s a good sign you need to check their alignment. Here’s what to do.

Required Tools

2 mm and 2.5 mm driver from the Traxxas Tool Kit
Pliers

Getting Started

Turn the truck over to access servos

Begin by turning the vehicle over. This gives you access to the servos, but also takes weight off the steering to reduce stress. You will need batteries in the vehicle for testing later, but for now the vehicle should be turned off.

Remove the servo guards

Remove both servo guards to access the linkages. Each guard is held on by two screws. If the guards are damaged, be sure to replace them when you finish.

Disconnect the linkage

Disconnect the linkages from each servo horn. Hold the servo horn tightly with your fingers to keep it from turning and possibly damaging the servo when you unscrew the linkage.

Disconnect second linkage

Move the steering linkages out of the way. At this point you may need to do some testing to determine which servo is damaged. Turn on your transmitter, followed by the truck, and try to steer in both directions. One servo may not turn at all or it may get stuck and not return to its center position. Clicking noises are another telltale sign of internal damage.

Remove the servo

Once you have determined which servo is bad, turn off the vehicle and remove the damaged servo from the truck. You will need to open up the receiver box to unplug the servo from the receiver. Either replace the servo or repair it with a new gear set. You must always use two identical servos with a dual-servo setup.

Zero out the steering trim

With the damaged servo replaced and plugged into the receiver, turn on the transmitter and vehicle again, but do not connect the linkages. Check the steering trim knob on your transmitter and make sure it’s pointing to 12 o’clock or zero on the dial.

Reattach servo horn

Straighten out the wheels on the vehicle. Notice that the servo horns on this vehicle are roughly perpendicular with the wheels straight. Try to align the horn onto the servo gear so that the linkage lines up with the hole in the horn. They may not line up perfectly. You should never have to move the servo horn in order to get them to line up. That’s why you adjust the length of the linkage instead.

Adjust the linkages

Use your pliers or a small wrench to lengthen or shorten the linkage by turning the knob in the middle. Keep turning it until you get the hole in the pillow ball to line up perfectly with the hole in the servo horn. Once you have them both aligned perfectly, turn off the truck again while you tighten down the linkages and horns. Remember to hold the horn steady with your fingers while you tighten it down onto the servo.

With everything tightened down, turn on the vehicle again and test your steering. With no input on the steering wheel, the servos should be quiet. If you hear a buzzing sound from the servos, they are not in perfect alignment. Try to realign them again until the buzzing stops. Failure to properly align the servos will cause undue stress and may even lead to servo overheating and damage. Once everything is aligned properly, it’s time to hit streets and have some fun. Just watch out for those RC-hating mailboxes!