42009 Mobile Crane MK II

Extending the arm

Are you having problems getting the crane arm to extend? It’s likely a few essential gears aren’t built properly. Go back to page 389 (page 49 of book 6/6), step 32 of the instructions and rebuild.

Position the yellow angular beam by pushing a black cross axle through the bottom hole. Building this part correctly will let you install the gears properly. With the gears now engaged, the crane arm will extend without any issues.
 

Adding the string

We’ve heard from some builders who’ve found it difficult to attach the string to the crane’s arm. With the way the black parts are shown in the building instructions, it can be a bit difficult to see how you attach the string.

This should help with steps 38-40 on pages 396-398 (pages 56-58 of book 6/6) of the instructions.

Step 38: The two strings are attached to stop them from falling through the set. They should be placed behind the rubber wheel, the ends coming out just underneath the wheel. You may need to adjust the raising/lowering option of the arm to position it properly.

Step 39 Part #1: Undo the strings and place the yellow 5m beam on top of them with the ends of the string tucked under.

Step 39 Part #2: Attach the ends of the string to the blue connector pegs on the bottom of the cross beam you inserted from the sub-step.

Step 40: Attach the 1X3 black tile on top of the stud ends for the string. You should be able to continue building now.