I am trying to build a vehicle with a sturdy steering mechanism powered by the servo motor. When I was a kid I did this all the time with a rack and pinion design, but now I don't have any of the rack bricks.

The best I have come up with is an axle connected to a universal joint connected to the steering bar (see pictures - note that some of the chassis has been removed to expose the steering).

The problem with this is that the steering is slightly offset to one side. Also the axle can easily pull out of the connector if there is any resistance to the steering.

Is there a better design I can use, while still keeping the vehicle relatively compact?

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  • You can also use a worm gear as a replacement for the older rack gear if you have any of those? Jul 26, 2017 at 14:11

2 Answers 2


Look at the instructions for set 42048 Race Cart. It has rack and pinion steering without using a rack. It basically uses the same 2-long beam as you use on the servo, but uses it to push two pins with towball end either left or right. You can find the instructions online at LEGO.com.

  • Phil B. is correct. Using the rack and pinion will allow the steering mechanism on that particular lego piece will allow you to be able to get around obstacles that you need to pass. Jul 16, 2018 at 0:45

I replicated the basic geometry of your steering build to use for illustration. I came up with two simple solutions that will work with your current setup. The steering servo is represented with a "M" motor because all of mine are in vehicles at the moment.

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The drag-link with ball joints setup can be greatly improved upon with ease, I just wanted to use examples that applied specifically to your current design.

I realize this question is old, I wanted to provide an answer for anyone that runs into a similar situation with their build and comes across this post.

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