Truck 8x4 with Detachable Lowloader (2010)


Building instructions (PDF)
(786 pages)
Example instructions (PDF)
Parts Inventory:
(3.763 parts)

Credit card and Paypal


See PDF for Bricklink XML upload procedure

Remote Controlled: Power Functions & Manual Controlled

Detachable lowloaders are used to transport heavy construction vehicles over the road by powerful trucks. These trucks are optimized for this purpose (engine, multiple axles, extra fuel tanks) and operated by specialized companies as Brouwer, Mammoet/Seumeren, van der Vlist to name a view in The Netherlands.

The requirements for this model were: Ability to load the original Technic LEGO® set 8275 (Remote Bulldozer), 8043 (Remote Excavator), 8265 (Front Loader) and the Prinoth Leitwolf snow groomer. As such, the gooseneck can handle a load of max. 3kg's. The challenge in Technic LEGO® was the stiffness and the pneumatic lifting construction of the deck. The truck is remote controlled, but can be switched easily into manual operation (steering, driving) by shifting gears on the model.


The dimensions of the total combination (Truck with Lowloader):
* Length: 130 cm
* Height: 21 cm
* Width: 16 cm
* Width with extended deck: 19 cm
* Weight: 4,7 kg (including batteries)

* Cargo weight: 3 kg max.
* Cargo length: 42 cm max.
* Cargo ground clearance: 2 studs min.

* Number of parts: 3.763


Photo-shoot (The Netherlands):
* Construct roundabout (exit highway A2) at Vinkeveen
* Road parallel at Amsterdam Rijnkanaal


The Volvo L350F wheel loader #42030 can easily loaded on the trailer!


Truck 8x4 (Remote controlled or Manual)
The dump truck 10x4 (see elsewhere on this site) was the basis for the design process of this truck 8x4, which means that most of the functionalities are comparable. The technic functions are: 2 axle steering, working V8 engine, differentials on both rear axles, power functions head-lights and power functions XL-motor for driving / M-motor for steering. Compared to the dump truck 10x4 - except from appearance (color, redesign grille and bumpers) - both steering axles are mounted 1 stud towards the truck's front side and are operated by the new 1x13 gear racks (part 64781).












Drive train: A power functions XL-motor is used to drive the truck. The force of the XL-motor is geared down in a two stages to the both differentials which drives the 4 rear twin wheels. The whole drive train is equipped with twin gears on each axle to apply the force from gear-axle to gear-axle. These twin gears are used to prevent damage to the gear tooth.
The XL-motor is pretty well able to drive the total combination, including a cargo load of 3 kg. However, my strong recommendation is to use only the 8879 'IR speed remote control' unit due to it's ability to control the speed of the XL-motor in multiple steps. Just applying the 'full speed' of the XL-motor from a 'stand-still' position of the total combination will result in too much stress on the whole drive train (as is done with the 8885 'IR remote control', who lacks the speed control).

5th wheel: A technic turntable is used for the 5th wheel, together with a static connection to the gooseneck (i.e. decoupling the gooseneck means removal of an axle-10 which can be easily done). The reason for this construction is to assure a smooth ability for the total combination to turn curves, as well to make sure that a detached gooseneck will stay connected properly to the truck.












The technic specifications of the 'Truck 8x4':
* 4 axle truck, first 2 axles steered
* Turning cycle correction for 2nd axle (with gears)
* Remote controlled, ability to switch to manual operation
* Working V8 engine, including fan
* differential unit on 3rd and 4th axle, interconnected
* Headlights equipped with Power Functions LED's

Non-technic functions are:
* Cabin doors open & close
* Cabin can be opened for engine access
* Raise-able wind deflector
* Towbar

Details applied:
* Dashboard with coffee machine and coffee cups
* Fuel tanks, air compressors and air filter units between the wheels
* Fire extinguisher, exhaust pipe
* Spotlights, flashlights, horns and airco-unit on cabin roof


The dimensions of the 'Truck 8x4' are:
* Length: 45 cm
* Width: 14,5 cm
* Height: 21 cm
* Weight: 2,3 kg (including batteries)

* Number of parts: 2.052


















Switch to manual operation (and vice-versa):
The truck can be operated with a remote control or manually. The reasons for applying this feature is make this model attractive to a broad audience. Especially young kids like to push the truck around, whereof older kids (and AFOL's) like the remote control.

See picture right for explanation.

Switch driving mode:
Within the picture, the truck is set to remote controlled (both 16 tooth gears in the middle). Shift each gear aside (one to the left, one to the right) to decouple the motor from the drive-train.

Switch steering mode:
In the picture, the truck is set to remote controlled. Shift the 8-tooth gear to the left to decouple the motor from the steering-train.




The truck is equipped with a tow-bar. This means that - for example - the drawbar trailer can be connected.











Detachable gooseneck with Lowloader
As seen on the pictures, the
lowloader is mostly build with the traditional studded bricks. Especially the deck is fully based on bricks, because bricks provide a much more stiff construction compared to studless beams. It took some development time to find the optimal balance between deck stiffness and minimal deck height with an acceptable ramp angle. The outcome is a deck being able to load cargo with a minimum ground clearance of 2 studs, with an acceptable sag of the deck when loaded with cargo.
The deck is mounted precisely in the middle of the 3-axle assembly, which has a pendular suspension mechanism. This is necessary to prevent tipping of the 3-axle assembly when the gooseneck lowers the deck. All the axles of the assembly consists of twin-wheels. The platform height of the 3-axle assembly is very low to support the bucket of an excavator.
Expansion of the deck width is possible by mounting so-called 'deck extenders'  which are stowed within the gooseneck stock area. These deck extenders are equipped with flashlights and warning signs.












The detachable gooseneck is able to handle a cargo load of 3 kg ! First I considered the new PF linear actuators, but again I experienced pneumatic cylinders have more advantages (appearance, necessary space, no difficult gearing system, force). Disadvantage is not being able to couple/decouple the gooseneck remotely, although manual assistance is needed anyway to mount the gooseneck firmly to the deck (by applying so-called 'locking bars' = axle's pushed through the technic holes in the deck and gooseneck).

The gooseneck has 2 independent pneumatic circuits. One for lifting the deck, and one for supporting the gooseneck on the truck's chassis when decoupled. The truck has an gooseneck 'auto-center' function; as such the gooseneck will center and locks when lifted.
The deck is lifted by 3 pneumatic cylinders in parallel and holds ~ 2 bar / 30 psi of air pressure when lifted with 3 kg cargo.

The gooseneck is equipped with a stock area, a spare wheel and ladders for access.















The technic specifications of the 'Gooseneck lowloader' are:
* 3 axle assembly, all with twin-wheels
* Pendular mechanism on 3 axle assembly
* Pneumatic cylinder support of the detached gooseneck on the truck
* Pneumatic cylinders (3) for deck lifting

Non-technic functions are:
* Deck width extension
* Buffers for securing the cargo

Details applied:
* Flashlights and warning signs
* Spare wheel
* Ladders for access gooseneck stock area




The dimensions of the 'Lowloader' are:
* Length: 102 cm
* Height: 16 cm
* Width: 16 cm
* Width with extended deck: 19 cm
* Weight: 2,4 kg

* Cargo weight: 3 kg max.
* Cargo length: 42 cm max.
* Cargo ground clearance: 2 studs min.

* Number of parts: 1.711





Struts to relieve pneumatic cylinders:
The pneumatic cylinders are continuously under air pressure when the deck is lifted. This will result in air leakage overtime, causing the deck to decrease and touching the ground in the end. As well, the life-time of the pneumatic cylinders is negatively affected when they are kept under air pressure for a long time.
That's why two struts are designed. These struts can be placed at both sides of the gooseneck lifting boom when the deck is fully raised, and will carry the load when the pneumatic cylinders are carefully deflated. As such, the pneumatic cylinders are relieved from air pressure.

Remark: The struts are not developed to carry the full cargo load of 3 kg's without preventing the deck to touch the ground due to sag. However, with less load (approximately max 1,5 kg), it functions correctly.





Mano meter (additional):
An additional mano meter (part 64065) can be mounted on the power unit of the truck. The gooseneck is already predefined to guide the pneumatic tube via the spare wheel to the pneumatic switches.