I'm building the Lego set 42131 D11 bulldozer 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.

1 Answer 1


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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