Losi RC Truck Needed Repairs

The Losi LST 3XL-E Monster Truck is One of the top Losi Trucks available. I have been running this Losi RC Truck for a while and it has been amazing. I have put this truck through just about everything possible. Dirt, mud, rain, 4-5″ actual standing water, snow, as well as high jumps and hard crashes.

Finally Needed Repairs

After about 7 months of constantly hard bashing, sometimes all day, several batteries. The Losi RC Truck is down for its first repairs. The Esc shuts down after about 2 minutes of run time and the steering servo shaft is worn out, there is a lot of play in the servo output shaft. I have got my new replacement ESC and Steering servo, so it is time to get the truck fixed up.

Replacing The LST Servo Losi LST Servo

Replacing the steering servo was fairly easy and Straight forward. Here is how I replaced my servo:

use the Allen wrench that comes in the package with the truck to take the two screws out of the servo horn. Then I slid the horn off of the servo, leaving the linkage hooked to the horn.

Remove the 1 screw holding the receiver cover and remove the cover to access the servo connector plug. Disconnect the servo plug and fish the wires out of the box.

Now underneath the chassis, there are two screws hold the ESC and Reciever mount. Remove the two screws and now you can lift up the whole assembly.

LST 3XL-E servo replacement

Remove the 4 screws holding the servo to the Receiver and ESC mount. Remove the servo.

Install the new servo, making sure it is positioned in the same direction as the one you just removed, The servo shaft needs to be facing the center of the chassis. Re-install the 4 screws.

Re-Route the wires back through the box and plug into the receiver.

Re-Position the receiver and esc mount back on to the chassis and re-install the 2 screws from underneath.

At this point, you want to plug in the batteries for the truck and then grab the radio and turn it on, then turn the truck on. Make sure the steering trim knob is set to center or 0 on the radio. Now turn fully to the left and then let go so it comes back to center position. Then to the right and back to center position. While doing this pay attention to the servo to see that it is turning in correspondence with the radio. Once the servo is at center, shut off the truck and the radio.

You can now install the receiver cover.

Slide the servo horn on to the servo shaft with the wheels in the straight-ahead position. Install the 2 previously removed screws and snug them down. Turn your truck and radio on once again to make sure steering is not reversed and the wheels are centered.

If the wheels are not centered, remove the servo horn and reposition it slightly and re-install. You can do this step until the wheels are centered straight ahead. If the steering is reversed for any reason, you can flip the steering switch on the radio and that will change the direction of the steering.

That is all there is to replace the steering servo on the Losi RC Truck.

Replacing The ESC

LST 3XL-E ESC Replacement

Whenever you need to replace the esc on your LST 3XL-E rest assured it is one of the easiest esc’s to replace. Here is how to replace the Losi LST ESC:

Remove the 1 screw holding the receiver cover and remove the cover. Unplug the sec connector and route the wires through the box.

Unplug the 3 motor wires from the ESC.

Remove the 2 screws holding the esc down. The esc has double sided sticky foam holding the bottom to the mount also. Use a small flat tip screwdriver and slowly and carefully pry up and through the foam to free it from the mount. Once free, the esc can now be removed and set out of the way.

Before you install the new esc, make sure there is double sided tape/foam on the bottom of the esc. This ensures the sec does not get shorted or damaged at all by being shook and joined by bumps and rough terrain.

After attaching the foam set the esc on to the mount and install the 2 screws that were removed previously.

Plug in the 3 motor wires, making sure they are in the correct order. Route the wires for the receiver back in through the box and plug into the receiver. Make sure to plug it back into the same slot that you unplugged the old esc from.

turn on the radio and then the truck, the esc should be all set and should respond to the throttle input from the radio. If it does, then install the receiver cover and screw. That is it!

That is how to replace the esc on your Losi RC Truck.

After The Repair

After I finished repairing my Losi, I had to take it out for a test run. Unfortunately, The batteries were not charged like I thought they were. I only got about 2 minutes of run time, which is not enough to see if it is completely fixed.

I will have to wait until the weekend to charge up my batteries and give it a good rip. Until then here is a video of my 2-minute run that I got. Hope enjoy the video.

2 thoughts on “Losi RC Truck Needed Repairs

  1. Great article, I was wondering how to replace my steering servo. Now after reading this article i was able to replace the steering sevro on my Losi LST 3XL-E, And it was not as bad of a job as i thought it would be. Thank you for the information and guide.


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