<p>You can adjust the length (extension) of linear actuators manually in two ways:</p>
<ul>
<li>The same motor would do - by rotating the axle on its end.</li>
<li>By rotating an extending shaft. Just make sure the other end is fixed, otherwise it would spin freely without doing anything.</li>
</ul>

CC BY-SA 4.0
2022-12-28T08:46:02.093Z
2022-12-28T08:46:02.093Z
Alex
<p>I'm building the Lego set <a href="https://www.lego.com/en-us/product/app-controlled-cat-d11-bulldozer-42131" rel="nofollow noreferrer">42131 D11 bulldozer</a> and my back ripper cylinders (linear actuators) are in the complete up position and it's keeping me from completing the build.</p>
<p>How do you get them to go down? I tried the control on my phone but it just keeps calibrating and won’t move past that screen.</p>

<technic><building>
Lego D11 ripper cylinder
Daniel Jones
# Lego D11 ripper cylinder

(Asked by: username_0 on 2022-12-27)

I'm building the Lego set [42131 D11 bulldozer](https://www.lego.com/en-us/product/app-controlled-cat-d11-bulldozer-42131) and my back ripper cylinders (linear actuators) are in the complete up position and it's keeping me from completing the build.

How do you get them to go down? I tried the control on my phone but it just keeps calibrating and won’t move past that screen.

**Tags:** technic, building


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## 1 answers

### Answer by username_1 on 2022-12-28. Score: 2

You can adjust the length (extension) of linear actuators manually in two ways:

* The same motor would do - by rotating the axle on its end.
* By rotating an extending shaft. Just make sure the other end is fixed, otherwise it would spin freely without doing anything.


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