LEGO GBC 9 – 4 Modules – 42043 Building Instructions

17.95 15.75

Detailed building instructions of the LEGO GBC 9.
Made from parts of LEGO Mercedes-Benz Arocs 3245 set 42043.

– Full HD PDF building instructions
– Brief with tips & tricks
– Pneumatic schematic
– and more

Difficulty level: Easy – Medium – Hard


Love Pneumatics, Automation and Action?
Then this GBC is definitely for you!


Example Full HD pdf Building Instructions


It has never been easier to build a complete LEGO Great Ball Contraption (GBC) loop yourself! This GBC is entirely built using only parts from the LEGO Mercedes-Benz Arocs Truck and uses 90% of all the pieces that come with it. Also to be referred to as model C of the 42043 Mercedes-Benz Arocs 3245. This module makes sure you master the LEGO GBC building techniques and tricks so that you eventually also can build your own GBC. The whole machine is powered by one LEGO motor which comes with the LEGO 42043 Set.


This GBC works great with our LEGO GBC balls.




The LEGO GBC 9 features 4 GBC modules which all work together to make a full loop so the ball flow will never end. However, it is possible to separate the modules and make your own unique configuration of combine with all our other LEGO GBCs!

Because this GBC is so big and all the modules are faced outwards you really have to walk around it to see and understand how everything smoothly works together. Great fun to build and a lot of WOW moments as you will learn how pneumatics, gearing, forces, mechanics and so much other cool contraptions work. This GBC really makes you think outside the box as you use the pneumatics, valves, springs in a whole new way so that in the end you have a full automated ball factory running on only one simple LEGO motor (included in the 42043 set).

The pneumatic full mechanical automated Crane Arm Module really steal the show. With timing mechanisms, gearing, controlled valves and pressure springs the crane completely works on it’s own, and believe us, it’s awesome to watch. The crane arm triggers the timings mechanism and fills up his bucket when the arm is in the lower position. Then the whole module will rotate 90 degrees by some clever levers and the whole crane arm raises via a slope. There the balls are released so they can move on to the Shooter Module.

The Shooter Module has it’s own unique filling mechanism. By adjusting the catch tray height and angle, the shooter module never misses a shot! Followed up by a Zigzag Module, the balls are blocked by the next timings mechanism waiting for the Tilt Lift Module to pick them up and taking them up to a higher level to re-run the whole loop again. All the timings mechanism are well explained and easy to assemble yourself.
Batteries can easily be replaced. Just slide the battery box in and out.





The LEGO GBC Balls are available HERE.















Change log latest update

v2: We included the length numbers for axles, beams and other parts. A high requested feature which is really usefull while building. We also made some other small changes. The building steps remain the same. Axle length on page 116 changed from 7 to 8. Make sure to get this update.

v3: Some small changes in the order of building steps to make the user experience better.


LEGO GBC 9 all over the world

Did you also built one of our LEGO GBCs yourself, with your friends or family? We would love to see and share it! Send us a picture or video at or via our social media channels.





2 reviews for LEGO GBC 9 – 4 Modules – 42043 Building Instructions

  1. I like this model sooo much , waiting it release and build it directly. The level of genius engineering is really high in this gbc and I learned a lot from it. A must buy!

  2. (verified owner)

    This is truly an amazing build. I often find myself building technic sets with an eagerness to have as much technic/engineering incorporated into sets as possible. While the Mercedes Arocs set is already one of my favorite, PV Productions blows Lego out of the water when it comes to creative, efficient implementation of Technic elements.

    Especially in this build, the combo of spring loaded catapult, pneumatic power with automated switching, and classic technic elements makes this build a one stop for satisfying those deep technic itches.

    Just a note: the pneumatic portion will take some adjusting, but follow the pneumatic chart included, closely. To adjust/align timing, I found it was helpful to adjust the red angled arm (used for rotating the claw) at the origin point – beneath the ball drop catch/ramp. Because axels are built with four sides, you can make adjustments in quarter turns to help align location to timing.

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