January 23, 2012

Mini Mobile Crane

After finishing my MOD of the LEGO® Technic 9397, I wanted to add pneumatics to other sets. My choice was the Mini Mobile Crane 8067.  I especially like the cabin so I wanted to reuse it completely. The mechanism of the outriggers is also well-done so, I reused them too.

To  make it more interesting I decided to use its parts and make an MOC loosely based on the Liebherr LTM 1200 5.1.

And this is what I came out with. 

All functions are comparable to bigger scale models like e.g., the 8460.

- 5 axle steering system actuated by a 20t, 12t gear reduction on the back
- Four outriggers stabilize the crane while lifting
- A rotating crane, mounted on the new turntable elements (99010, 99009)
- The crane is lifted pneumatically with a Pneumatic Cylinder (47224c01)
- The crane consists of two booms so it can extend
- A hook with rope
- Dummy engine

The most difficult part was the steering system and it took several attempts to realize it. I got inspired by the LEGO® Technic 9390 and developed the idea. This result in a modular system of small size. The turning radius is nearly 40 cm.   

Note: None of the axles are meeting in a pivot point which causes some problems (slipping wheels, vibrations), especially on the front axle. I made this compromise according to the small scale.
More detailed pictures of the steering mechanism to be found on Brickshelf.

The Boom is lifted by a Pneumatic Cylinder (47224c01). Two Small Pumps (x191c01) provide the air and I used a Technic, Shock Absorber 6.5L, Complete Assembly (Normal Spring) (731c05) to run the pumps manually. With an 1L stroke you have to push about 20 times to lift the heavy boom.

The boom is extendable and uses Erik Leppen's design. It's really strong and fits the scale quite well.

I'm very happy how everything turned out and I hope you like it as well.

More detailed pictures to be found on Brickshelf.
Check if you have all the needed parts to build it yourself using Rebrickable.com
You can also download the LDD File directly.
LEGO® Digital Designer lacks in some parts, you have to replace the fake parts of these:
- Pneumatic Cylinder (47224c01)
- Two Small Pumps (x191c01)
- Pneumatic Switch (4694b)

With best regards,


  1. Hi,

    I built your incredible mini mobile crane (if you want photos I should send you some of them). This moc is really complex and I would not have been able to reproduce it without the ldd file and building notice from ldd (I'm a bit ashamed but I have to tell the truth).

    However, I probably made some mistakes so I would like to ask you some questions :
    1. the steering system is really cool but... Do I built it right, because, when I turn the back HOG to the right, the wheels (and the truck) go left
    2. I had to use a 3/4 technic pin (http://www.bricklink.com/catalogItem.asp?P=32002) linked to a 1*3 thin liftarm to build the front of the truck but this part do not appear in your part list so i assume that i made something wrong but what ?
    3. I think there is an error in your ldd file about stabilizers : the 1/2 pin used to stop it is not in the right hole

    1. Thanks for your precise feedback. You are right about every single point mentioned.

      1. The steering system needed some reduction so I chose to add the 12t gear, which changed the direction.
      2. I've sent an email to add two pins in the parts list.
      3. Just edited the LDD-file.
      I'm really thankful for you pointing this out.

      Best regards, Jan

  2. What length is the string?

    1. It's about 1 m long. I think it's from the Rescue Helicopter 8068.