42043: Mercedes-Benz Arocs 3245 review

Trucks. Gotta love ’em. They are just huge things that transport stuff en mass and such. Like my taste in cars, I do love my commercial vehicles from the 60s up to the early 80s. Classic workhorses and stuff I grew up looking at. At our local street market there was always a Bedford TK or a Ford D-Series parked with lots of fresh produce on the flatbed. Let’s also not forget the Leyland vans and trucks like the Clydesdale tanker, 350 EA, the list goes on.

Today, the market is dominated by the likes of Mercedes Benz with the Sprinter chassis seeming to be more popular than the Ford Transit by all accounts. Daimler AG have made real inroads into the commercial market, and more so with the truck range when once it was dominated by the FH12 from Volvo. Competition is fierce with the likes of Hino, Scania and PACCAR (DAF Trucks) all muscling in on the act.

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The most famous ones are the L-Series and the NG Series which you may well see on the roads of Asia and Africa today even though the designs are more than 30 years old.

Today the ‘Bad Bwoy’ of the range is the AROCS . Introduced in 2013, it is mainly aimed squarely at the construction sector and a real, proper workhorse.

Now, LEGO has had of recent times a relationship with Daimler AG, which to me is quite something. To put into context and a slight aside, Mattel cannot produce any 1/64 Hot Wheels/Matchbox models as they refuse to apply the Daimler AG licensed hologram on the packaging. (It should noted other brands like Siku and Bburago don’t seem to have this issue………). So this paves way for a licensed model, which in my book is great news.

Back in 2010, LEGO gave Technic fans the U400 Unimog. This was a flagship set with full independent suspension and a power crane grab actioned via the LEGO Technic-driven motor. I enjoyed the set immensely and had to marvel at the way the model was put together. It took me about 3 weeks on and off making it, with the total time around 10 hours.  A super set.

But within the period that the set was retired, there was little in the way to get me excited about any Technic sets. Most of them didn’t really appeal, which was OK, as it saved me spending £100s on stuff.

But then LEGO pull out the AROCS 3245 – 4×8 wheel, config, 4-wheel front axle steer with independent struts, V2 Pneumatic function, Licensed model. Technic, 2700+ parts… I could go on in this petrol-head manner.

For me it is like a bull to a red flag. And what better thing to ask to have for my birthday. I was waiting for the October VIP Promotion from LEGO, but the local retailer had CHF50 (around £33) off the RRP so this was a good price for an expensive set.

This is going to be a long review, but let’s not do things by halves – this is a flagship set and thus deserves the attention.

Official description

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Climb aboard the awesome Mercedes-Benz Arocs 3245! This huge, robust, 2-in-1 LEGO® Technic model is packed with authentic details and features. Turn on the included Power Functions large motor and engage the advanced pneumatic system (new for fall 2015) for complete control over an array of exciting motorized functions. You can operate the ultra-versatile crane arm mechanism, open and close the grabber, extend the outriggers or raise and lower the tipper body! Twin axle steering, double differential drive and fully independent suspension provide ultimate manoeuvrability, and the driver’s cab tilts to reveal a detailed 6-cylinder engine with moving pistons. Open the cab doors to access the detailed interior with dashboard, blue seating and steering wheel with Mercedes-Benz logo. This meticulously detailed 2015 model also features an extendable crane arm, 4 suspended axles, double wheels on the 2 rear axles, opening tailgate, warning beacons, wing mirrors and comprises 2793 elements, making it the largest LEGO Technic model ever produced. An authentic white, grey and black colour scheme and iconic 3-pointed Mercedes-Benz star add the finishing touches to this impressive model. When you feel like another building challenge, rebuild it into the rugged Mercedes-Benz Articulated Construction Truck.

  • Features a LEGO® Power Functions large motor and an advanced pneumatic system for an array of motorized features, including extendable outriggers, automated crane arm and grabber, and a working tipper body
  • Also features 2 suspended front axles with twin axle steering, 2 suspended rear axles with double wheels and 2 differentials, fully independent suspension, 6-cylinder engine with moving pistons, detailed cab, opening doors and tailgate, and a 3-pointed Mercedes-Benz star
  • Includes 2793assorted LEGO® elements
  • Activate the LEGO® Power Functions!
  • Engage the pneumatic pump!
  • Extend the outriggers!
  • Ultra-versatile crane arm mechanism!
  • Tilt the cab to reveal the engine!
  • All-round independent suspension
  • 2-in-1 model: rebuilds into a Mercedes-Benz Articulated Construction Truck
  • Crane arm reaches up to 57cm into the air
  • Mercedes-Benz Arocs 3245 (with retracted crane arm and outriggers) measures over 12” (31cm) high, 21” (54cm) long and 5” (14cm) wide
  • Mercedes-Benz Articulated Construction Truck (with crane boom extended) measures over 22” (57cm) high, 29” (75cm) long and 6” (17cm) wide, and 11” (28cm) high with crane boom retracted


The review

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So for this review, I am going to be looking at the build from a bag by bag basis. I think that it will give the BF reader a good idea of what the build is like and also prepare those for the challenges ahead when they get around to the build.

The box is a big one – and with 2700+ parts, no wonder. The style is as per all other Technic sets, black with splashes of orange. The lid flips up to reveal the workings of the built truck, etc.

Now, regular BF readers will know that I refer to instructions as maps. I always have done, and being an old git, I am resistant to change. But more times than most the big Technic sets come with books of instructions. Indeed, 8110 U400 Unimog came with no less than 5! And thus begins the problem of storage. For that set, I have five specialist clear wallet pouches that fit in an A4 arch lever file. And they take up some space.

LEGO have finally seen a bit of sense and give the builder a 470 page (I kid you not) manual. It weighs a ton. BUT everything is in one book which saves the need to constantly flip between them all. It is immense, but also at the same time very satisfying. It gives you a sense of how complicated the build is going to be. I am a big fan, so well done to LEGO on that front.

Inside we find 6 stages worth of bags, along with separate wheel/tyre and pneumatic bags. A lot of parts for a very big truck.

Bag 1

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Bag One creates the front cab chassis and engine block. This is quite a satisfying part of the build as you create the engine and the front four wheel steering as well. I was not sure how it would all work with independent struts per front wheels in terms of suspension, but the grey coupling arms which hold the front axle are key to the truck’s inner workings. Surprisingly, the front shocks are the yellow suspension units which are a little harder than the traditional grey ones. I would like to swap those out to see if it makes a huge difference.

The engine block is a straight six with a longitudinal mount (naturally). However I did notice that when I completed the Bag One build and with the ability to turn the gears whilst they are not fully connected to the truck as a whole, the engine was simply running far too quick for my liking. Pistons were going up and down faster than someone running for the last train home after a heavy night. It looked a little ridiculous. So I looked at swapping the gears around, with the large gear on the crank and the smaller one on the drivetrain.

This seemed to work in principle, but then I had the age old issue of missed timings when the smaller gear was not powerful enough to turn the large gear…….cue gear grinding. I don’t know if it was intentionally done by LEGO to have the gearing turn the crankshaft at such a high revolution, but it just looked a wee bit daft. Therefore, the old parts bin came into action with two middle sized gears going on in place where the axles for the crank and drivetrain were respectively.

Job done. Gearing it down gave a more authentic feel to the engine and the cylinders were firing at a somewhat more normal rate rather than that of a race car.

Perhaps the normal LEGO builder will not be bothered. Petrolheads will be. As I said, I cannot understand for the life of me why LEGO geared the engine so high……….rather daft.

Anyway, once bag one is complete, you get to see how the front of the truck is created and also marvelling at the way the four wheel steering works on independent front suspension, with the key four elements being the grey beam 4m ball cup ø5,9 without friction as well as a the LT steering gears. It is a really great little piece of engineering and again takes it up a level from that of the U400 Unimog.

Bag One just completes the front section and lays the foundation for the rest of the truck build with the Power Motor being the main driver of functionality.

Bag 2

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Bag 2 – I have to admit – is not exciting at all. This bag created the stabiliser feet (outriggers) assembly as well as the prep gearing for the power functions for the rest of the truck. It is all a bit repetitive and not that much fun, but it is needed as it serves a purpose. It’s not like you are putting together a full engine assembly………

I can’t get all hyped about this part of the build. It is a bit dull.

The main new part is the housing 2x15x3m f/gear rack – red arms that are used for the stabilisers as well as the crane arms as well. It is a very unique element, where in the past this would have been created with the 1×16 Technic Beam and 1×4 teeth. Again, not exciting, but necessary.

Bag 3 – rear chassis and wheels

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Ah, this is more like it. Bag Three sees the coming together of the chassis for the AROCS and the marvel of the rear wheel assembly. Now this is where the nerd in me comes out. I am really impressed with the way that the rear diffs are linked together and are ‘independent’ in terms of set up. It is a lovely bit of engineering and possibly – for me – one of the highlights of the build. Rear wheels connect to the crankshaft and engine block through a series of linkages. As I mentioned in the Bag One review, the engine spins far too fast for my liking, so it was geared down. And with the addition of the rear section, this now puts the whole thing into sync.

Seasoned pros will fly through, but will admit I made a few mistakes. Namely because I am half watching Sons of Anarchy and it was very late at night as well…….(who says blokes can’t multi-task). But this is part and parcel of Technic builds and it also sharpens the mind. The one thing I would note is that at times the instruction within the manual are not that clear and it does take several reads to ensure that you have built correctly. So at times, it is not necessarily obvious where the construct should go and that leads to a little puzzlement when things don’t look right.

The rear of the truck also creates the tipper lifting jack via the use of power function and gearing. Couple this with the battery box and you have rather nifty power jack. Works flawlessly, but the only trouble is that if you do not cut off the power, you will grind out the gearing.

This is a good bag of creation and really does pull the whole framework together.

Bag 4 – rear crane.

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Make no mistake, this is challenging – more for the fact that you HAVE to ensure that your pipe work is spot on. I remember the first Pneumatic sets such as 8843, Fork Lift, you were given the piping and you had to cut it to size. Not anymore, but you still need to separate and check the given tubing. I tried to do by sight, but ended up re-doing the pipe work which was a little time consuming. It is not easy and the young builder may well struggle. I find this more a challenge and ultimately you QC your build. The pneumatic pumps are nothing new as far as I could make out.

Most of the time you are ensuring that your work is neat and tidy in terms of connecting the hoses and ensuring that they match what is in the manual. Some may find it easy. But complacency will lead to issues. Not a lot of bag parts, but still very challenging.

New parts include the crane grabs which are two separate pieces.

Bag 5 – Cab Unit

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Ultimately satisfying as this “makes” the truck. Nicely made, and really does capture the distinctive style of DaimlerBenz trucks well esp. at the front. Great stuff. However, there is a flaw and the curse of the steering wheel comes into effect again.

What I have done with my build is re-jig the layout to reflect right hand drive. It would be very cool for LEGO to give an alternative plan on how to do this – naturally Denmark is in Europe and the majority of their cars are LHD. It is not that difficult to do, but I think the option should be given. I have done this from day one with the likes of 8860 Technic Car Chassis. I do wonder how many others would do the same.

Not complex, this can be fiddly in places, but again, another step to completing the model as a whole.

The majority of stickers are used at this stage as well as the use of the three pointed star printed on a round edge (The Merc symbol). No doubt that this would be a much sought after piece to have and I am already thinking of how I can create a G63 AMG from Technic……..then again that might be a little too ambitious.

The one thing that once again has annoyed me is the stupid steering wheel. It looked daft on the Mini Cooper set and looks daft on this model as well. Just bloody massive and out of proportion. Why on earth can LEGO not create a new part and effectively scale it down to meet the requirements of the model? D’oh!

Bag 6 – Tipper housing.

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Very easy construct and the final item of the build – less than 20 mins to make. Nothing complicated about it. Just sits nicely on the rear, but care needs to be taken in attaching it as it is not that easy.

You can also rebuild this as a Articulated Construction Truck

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Conclusions and thoughts.

Make no mistake, this is a super model, but not without some minor gripes.

The chassis is brilliant. I will bang on about this again, but the construct of the wheel set up and suspension units are a joy to make and can give scope to take a MOC to the next level. It is something us closet engineers love to muck about with and just wish we were on a level like Sariel!

Battery box is nicely hidden within the truck, which sits nicely at the top as opposed to the way it was mounted for the U400.

The cab is very realistic and well captured. This has spawned a host of MOCs based on the design, so it is testament that even the hardest of MOC-ers acknowledge this as a platform.

Tipper unit is fun as well as the stabilisers. Crane jib is frustrating in operation due to the pneumatics and seems like there is a hangover from the U400. Now I am not sure if this is my building skills or if it is just like that for everyone, but I can never get a fluid operation with the crane jib. Perhaps some remote control functionality could have been applied…..I don’t know.

I am going to list below what I believe are the flaws within the build:

  1. Instructions can be a little misleading – needs to be clearer in places
  2. Stupid steering wheel – why on earth can they not create a new one? It looked stupid on the Mini Cooper and also looks daft on the truck. Poor, poor decision to use this part.
  3. No auto shut-off with motor – this can lead to gear grinding unless you manually attend to it.
  4. Pneumatics are temperamental at times – doesn’t do what you are directing it to do………again, not sure if this is me or if other builders have had the same issues.
  5. Front axle struts are too taut for my liking. I would have preferred the softer dampers as per the rear of the truck. And with this it also leads to far too much space between the wheel and the wheel arch.
  6. If only the lowering of the stabilisers was motor driven!
  7. Engine gearing from drivetrain is geared too high.

Despite my gripes, overall I am very impressed and takes the notch higher than set 8110 Unimog U400. From an engineering view, it is great to see how the four wheel steering is connected in conjunction with independent springs as well. TBH, I found the rear of the truck even more impressive with the different diffs doing their job as well as giving ride with the dampers.

The stabilisers are a nifty feature – again, you can see how this improves on the initial canvas of the U400. At £170, it is not cheap, but provides far better value per part than 42030 VOLVO L350F. The build took me around 15 hours over a 4 week period. Yes, I made mistakes. Not afraid to admit that, but that was half the fun – resolving issues and getting it right.

I am not sure if this is for everyone. I suspect many will be indulging in LEGO Dimensions or such, but as I have zero interest in gaming and the like, this is a perfect substitute. For car nuts and budding engineers of the future, this AROCS set hits all the notes with the occasional flat part.

It does get through to the Live Shows having endured my build Boot Camp.


My name is Keith and I am a AFOL. Currently an expat living out in Basel, CH, but have a firm footing back in the UK when time permits. I have had had Lego ever since I can remember - and only until my wee one came along have I re-kindled the flame for building again. I also run matchbox1-75.co.uk, a resource site for the 1-75 series of miniatures by Matchbox. There are only three themes that I am get/collect (finances permitting) - City, Creator (Advanced and Expert) as well as the classic Star Wars sets from Eps IV to VI (anything else does not exist). I also keep an eye in Europe with ample chance to see how France, Germany and Switzerland market and offer LEGO.

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