Complete sets


Monday, November 12, 2012

Peterbilt 379 & CAT C15

Since I was a child I has been a fan of big trucks, and specially of American style trucks(in Spain is strange to see trucks with long noise).

For this MOC I have chosen one of the most charismatic and representative models of these trucks: a Peterbilt 379.

Also I have endeavored to put a version of CAT C15 engine (I'm also a fan of the brand CAT).

This MOC is made in a 1/10.2 scale, giving a final size of 31 studs width, 99 length and 40 high.

Here you can see some pictures taken in Skaerbaek where you can appreciate the size, there are: this Pete, the Crow's Vampire GT(scale 1:10 too...), the Nathaniel's Supercar and my Veyron.

The total weight is 5.5kg, and has been one of the main problems I've had. Front axles deforms and look like the wheels has huge camber angle. This is a esthetic defect which I hate, but it has not solution if I want to keep all functions and therefore the weight of the truck. I will try to fix it comming soon.

The electric system is huge, and it has:

- 2 AA PF battery boxes
- 4 PF IR recievers
- 5 PF XL motors
- 5 PF M motors
- 1 PF switch
- 3 PF large extension wires (50cm)

Probably, the most “wanted” picture for Lego Technic followers:


When did the truck I always wanted to do it complete, including the sleeper, but later I had to discard it because the cost would have been huge.

The hood can be raised, and remove if you want removing only 2 axles.

Also if the hood is open, you can remove the steering wheel and before remove the cabin in one piece just pulling up on it. Under the cabin you can find both AA battery boxes and the 4 IR receivers.

The two huge fuel tanks are used to cover part of the mechanisms of the truck: on the left the mechanism of the gearbox and on the right part of the pneumatic system.

As curious data, only the bodywork weight is more than 1 kg...

CAT C15 Engine

Under the hood you can find a replica of the CAT C15 engine, with its 6-cylinder in line.

The engine doesn't have the sides covered to appreciate that the cylinders are located in the same order as the real engine, with 120 ° intervals between them. Getting those 120 º between cylinders was very complicated but I thought it was necessary to be more faithful to the original.

The engine also has a motor M to rotate it, which is connected directly to a battery. Between the engine and the M motor there are a differential, which is also connected to the drive motors, so that the engine is always at idling, but when you starts the drive motors the C15 accelerate adding both speeds. The rotation speeds grow up from 250 rpm up to 700 rpm aprox.

Pneumatic system

After almost 10 years without using pneumatics in any of my MOCs, I decided this was the perfect model to use it.

The pneumatic system the truck runs along the complete truck, mainly controlling the suspension and brakes on all axles.

The pneumatic system is composed mainly:

- 2 Small pumps (6L)
- 1 Large pump (for emergencies).
- 2 Air tanks
- 7 Small cylinders
- 8 Large cylinders
- 7 Valves
- 1 Manometer (LEGO part n.64065)
- 22 T connectors
- And about 5 meters of pneumatic tube in 3 colors: blue, black and light gray.

The pneumatic tube color code is this:
- Blue: general system and suspension
- White: Brakes on
- Black: Brakes off

All pneumatic control is located on the right side of the truck inside the fuel tank.

The pneumatic system starts in the air pumps. A M motor is responsible for operating them asynchronously.
The compressor has auto-stop system, it stops approximately at 2 bars pressure, and restart in 1 bar. This compressor control uses a small cylinder, a PF switch and a small spring to counteract the cylinder. To have enough air to the suspension and brakes the truck has two air tanks, they are located inside the chassis and just above the gearbox.

Also in the cab, between the seats, there is a manometer to measure the system pressure, it is very useful to know how much air have you at any moment.


As the real truck it has live axles. Both rear axles are driven without differential between them.
In each axle between the differential and the wheel the axls has gear ratio 12/20 to reduce necessary torque in the differential and protect bevel gears.

The front axles uses the same steering system as the real Pete, of course the steering wheel turns too, also it turns 4 laps, again as the real Pete

- Suspension

The suspension is fully pneumatic in all axes, and it doesn't use any spring to help.
The front axle has 4 big cylinder and each rear axle 2.

The cylinder are controlled by a valve connected to the same axes. So that the truck can maintain the height to the floor regardless of the weight above it. If the weight increases the suspension is compressed and the valve opens getting more air into the cylinders, then the suspension turns to stretch and returns to its normal height and the valve closes.
If the weight is reduced same thing happens, the valve opens and lets out some air until the pistons down to the normal position.

- Brakes

The brakes as the real truck are drum brakes, there are a drum on each side of each axle, all of them controlled by a small pneumatic cylinder.
The control of these pistons are made through two valves, one for the front axle and one for the rear axles.

For normal braking the brakes operate all at the same time, but only while you are keeping push the brakes botton.

But you have also parking brake mode, if you push the brakes botton in the opposite direction only rear brakes works, and they will not disabled if you stop pressing botton. To remove the parking brake you only need use the normal brakes.

- Auxiliar output

Behind the cabin there is an auxiliar pneumatic output(blue connector), where you can connect anything you want. The valve to activate it is located before the rear-right wheel


The transmission is the biggest mechanism of the truck, and it has an approximate size of 25x7x45 studs.
It uses 4 XL motors for drive.

The transmission has 18+2R speeds(this is true, is not a joke...).

The transmission is divided in two parts: the main gearbox with 9+R speeds with automatic clutch(this gearbox is based on the LR Defender), and a transfer case with 2 speed (H and L)

The main gearbox uses a XL motor to shift gears, it has a speed indicator behind the cabin, and speeds ratio are the next:

1 - 1:0.36
2 - 1:0.48
3 - 1:0.6
4 - 1:0.8
5 - 1:1
6 - 1:1.33
7 - 1:1.67
8 - 1:2.22
9 - 1:2.78

The transfer case uses a M motor, and the speeds ratio:

Low (L)- 1:0.9
High (H)- 1:1

Joint both gearboxes the result is this:

1L (1) - 1:0.324
1H (2) - 1:0.36
2L (3) - 1:0.432
2H (4) - 1:0.48
3L (5) - 1:0.54
3H (6) - 1:0.6
4L (7) - 1:0.72
4H (8) - 1:0.8
5L (9) - 1:0.9
5H (10) - 1:1
6L (11) - 1:1.2
6H (12) - 1:1.33
7L (13) - 1: 1.5
7H (14) - 1:1.67
8L (15) - 1:2
8H (16) - 1:2.22
9L (17) - 1:2.5
9H (18) - 1:2.78

Auxiliar electric output

As I said before, the truck has an auxiliar pneumatic output, but also it has an auxiliar electric output too.
There you can connect anything you want, and control it with the remote controller.

To avoid leaving this connetor without any use I have added a fifth wheel(trailer connector).

- Fifth wheel

Note: right now I don't have intention to do a complete trailer.

It is very simple and effective. The kingpin diameter is 1 stud.

The fifth wheel is on the chassis, but it is not part of it. You can remove it removing only 4 pins.

Finally as always, you can see a complete video with all features showed:

And see all pictures here:

I hope you like it!!


Jorge said...

When I read C15 I was so shocked, oh my god this time a citroen ;). Great job as always.

Anonymous said...

this is the most ridiculously awesome lego creation i have ever seen! great build and very inspiring~

Zachary Cross said...

Fantastic as always, And i think that, although it's huge, it's compact in the way you fit all those parts and functions in that space.

tuur said...

OMG best moc ever !!! but there is one litle thing:
I can't see how the brakes work, I now that the two rubber part's turn in but they nearly doesn't touch the axle. how does it work's??

Sheepo said...

The rubber parts doesn't touch the axle at any time, they touch inside the black small wheel inside the big grey wheel

tuur said...

and does this system also works for the front axle (with steering)??

Laurens-wuyts said...

VERY GOOD! And for make it litle better you can make a trailer. (^_^)

guicarhobby said...

The trailer???

dokludi said...

Very, very good MOC!!

Blastem said...


Anonymous said...

Can you put instructions for the 5th wheel please!

Unknown said...

Will you upload pictures of the drivetrain/differentials?

Sandesan said...

Nice. Now th elong wheelbase makes sense: a sleeper would have looked great, but after Denmark and NYC, I understand your hesitance...;-)
I especially like the breaking system. What's next? Building it into a wrecker?

Esteban said...

Absolutely marvelous!!! You should contact Peterbilt. In their online shop they sell golf balls, for god's sake. Every Peterbilt fan would love to have your kit. Congratulations!

Anonymous said...


Anonymous said...

weren't we going to get instructions for the gearbox, in 5+R format (from the defender?)

Unknown said...

Hey Sheepo! This is an awesome truck! Do you know any good and compact 3+R gearboxes for RC's? Thanks!

Anonymous said...

Muy buen MOC al igual que el Defender!Necesito instrucciones y lista de piezas!Me encanta!

Anonymous said...

Looks giant. Then you realize those are Mog wheels.You made Mog wheels look small. I was pretty sure that is impossible. Can you upload some instructions for the 5+R gearbox in the Land Rover?

Driva00's Creations said...

are you going to make instrucktions for the gearbox?

Anonymous said...

how do you connect so many motors to the battery box without the overload prevention system kick in?

Sheepo said...

Very simple, never will work all motors at the same time.

cmnxt said...

This is an awesome truck!
I translate it into Chinese,and published on a Chinese Lego forum.(
Hope you not to mind.
Thank you for your works.

tuur said...

are there goeing to be any pictures of the skaerbeck event

Anonymous said...

in your land rover defender, you had two xl motors going at the same time without having the overload prevention system kick in when you shifted gears. how did you do that? my battery pack doesn't even allow two xl motors.

Sheepo said...

Maube you have problems with your battery box, because I can connect 2XL+M motors full-load without electric overload... or 3XL in mid-load... of course my batteries have NOT been modified...

Anonymous said...

Hi Sheepo
Great Build - i saw at skaerbaek in DK.
Can you post some pictures of the compressor auto-stop system ??
I would like to see how you did that.

Kind Regards

Sheepo said...

Now I don't have time to do it, but this is a great idea, I will do as soon as get some free time.

Anonymous said...

A result of pure creativity and value-add to details.
Respect! I love everything of your work!

I got a question:
It´s the first time with a "running" motor, isn´t it?
In the description you say, it´s working with a differential. Can you explain it more or even show this function with a picture? (instructions would be the best ;) ). Thanks, Greeting to Spain!

Anonymous said...

And how does the function work, that the pumps are stopping, when they reach maximum pressure? Does the Manometer have this kind of function?

Sheepo said...

[It´s the first time with a "running" motor, isn´t it?] Honestly, I've never seen this mechanism before, but I don't know if someone has already done it before ...

[Does the Manometer have this kind of function? ] No, the menometer only show the presure, it doesn't have any function to stop the pumps

Anonymous said...

The automatic compressor is a well-known idea. just a cilinder connected to a switch. when pressure goes up the cilinder extend and switch of the power. As a counter force a elastic belt or a spring is attached to te cilinder. A high pressure allows the cilinder to overcome the counterforce. that's all

Sheepo said...

I never wrote that the automatic compressor was invented by me...

Anonymous said...

I didn't say that. SORRY if I make you feel I did. I just explained how it works!

Anonymous said...

It´s a nice truck but
what is the part number of the brake drums?

mfg Peter

Sheepo said...

The drums part number: 60208

Anonymous said...

Ok, thank you!

Anonymous said...

I am really impressed by the C15 engine: How did you manage to get a 120 degress alignment? Did you use pulley wheels to build the crankshaft?

From the pictures, it seems that you also didn't used the "standard" rod. I am really curious to see I you build it...

Sheepo said...

The crankshaft uses wedge belt wheels to get the 120 degrees. and the rod is made with a ball-axle, an axle connector, a 4L bar and an angle connector.
Comming soon I will made some more pictures and instructions for some of the "strange" mechanims of the truck ;)

Andre said...

Hej Sheepo,

I considered the 911 as masterpiece, but you proofed us wrong again. Awesome. And I'm proud of myself constructing a real speed/momemtum sensing differential in Lego (always powering a wheel with at least a certain amount of motor-momentum)... Piece of cake!

Unknown said...

can you pull off the front tires and show us how it works please!!

Sheepo said...

Sorry but, how works what? the brakes?

Unknown said...

yes the breaks please, sorry...

Unknown said...

the 5th wheel trailer hitch, how does that work?

Impreza09 said...

You really need to buy metal axles at this level.. Atm you're really the best builder I know of.

Unknown said...


now i won't be the first to use unimog tires on a lego truck anymore!!!

Anonymous said...

Sheepo you are the BOSS !!! This is awesome

Anonymous said...

Will you make complete instructions for this truck? Would pay for it too ;-)
Best build Ive ever seen in my life. Respekt!!

Sheepo said...

Maybe in a very far future... but very very far hahaha

Kwon8429 said...

whoa..... just awesome creature....

Anonymous said...

I love this!!!!!!!!!!!!!!!!!!! can you please post a picture of the crankshaft of the engine

Sander said...

Sheepo, you mentioned the front suspension results in too much 'Camber' due to excessive weight. How is the front tire connected? Via the axle hole, or via the surrounding pin holes? It seems that the Unimog tire itself is eager to 'bend' when emrely connected via the axle hole...

Sheepo said...

The wheel is connected using the axle hole. If I use the pin holes I can't put brakes. But in any case I fixed the axle problems some months ago.

Unknown said...
This comment has been removed by a blog administrator.
Anonymous said...

how did you get the negative camber to go away? if you still have it built could you post a picture of the better front axle? thanks

Anonymous said...

Anonymous said...
Will you make complete instructions for this truck? Would pay for it too ;-)
Best build Ive ever seen in my life. Respekt!!
January 17, 2013 at 11:41 PM
Sheepo said...
Maybe in a very far future... but very very far hahaha
January 22, 2013 at 5:25 PM

Meanwhile, in the verry verry far distant future .... ;)

I know a little boy who never got a gift for the holidays, whenever he was good he did get a Lego block.
After all these years, the boy had enough cubes.
But he does not plan anything to do with it
until he saw a beautiful truck on the interweb ....
the best gift for the upcoming holidays
are, of course, the instructions for building a truck.
Not any course, but those he saw at Santa Sheepo his site.
So please Santa Sheepo, provide us instructions and the following year he will again be a good boy .

and the land-rover, he has since yesterday so that is not an option ;)

Anonymous said...

Hi Sheepo ,

could i get some more detailed pictures , i'm willing to pay for it .
I realy want to make this one !!!!

Regars ,


Anonymous said...

Is this truck one that can be bought? or is any of your trucks for sale?

Anonymous said...

It's amazing!!! congratulations :) it's possible to have the instructions?

Anonymous said...

Could u by chance Show us the Crankshaft for the engine? or just instructions for the engine

Unknown said...

can you make a instrusction of just the gears in the gearbox

Anonymous said...

Bonjour sheepo
Allez-vous faire des instructions complètes pour ce camion? après la construction du land rover 110 qui est une merveille, j'ai hâte de m'attaquer a se camion qui a l'aire vraiment superbe de technique.
toute mes félicitations

Sheepo said...

Je suis désolé, mais je n'ai pas l'intention de faire des instructions pour ce camion.

Anonymous said...

Let my think: This truck cost 1500 euro. Will you post all info about the Camion 8X8 please. And are you planning to make instructions for gearboxes?

Anonymous said...

Sheepo can you please make instructions for your Peterbild? I think many people would pay more than 20€ for this amazing truck.

Unknown said...

Since it's so long, what's the turning radius?

Anonymous said...

Will you be selling the instructions soon for the Peterbilt 379? Please let me know as I do like that creation.

Also, do you sell one that sounds like a real truck when you switch the gears?

Anonymous said...

Hi, I was wondering if you would be selling instructions for the Peterbilt 379 soon, I hope you do because I think it is your best creation.

Unknown said...

Hi, Sheepo, do you have building instruction?

Anonymous said...

great model

David said...

I would very much Love too see how you did the valve for the suspension. Whether you show it or not is fine. Still love your work and for all that you do, thank you.

David said...

Never mind I finally see it in the video.

Unknown said...

where I find and buy

Sheepo said...

Nowhere, I don't sell instructions for this model

Felix said...

when will you sell instructions for this model?

Sheepo said...

Probably never, it is too big and complex

Aleh said...

What a pity :(
I'd buy it if you decided to make an instructions

Anonymous said...

Its amazing how you are able to fit independent suspension and brakes into sush a small space. How do you do it?

Unknown said...

What! Nevers! Ill pay a lot of money for chose instructions.This truck la awesome

Anonymous said...

Hi Sheepo
The Large cylinders for the suspension are connected by what means to the chassis?

Steelman14a said...

Is there an instruction for this is avalible?

Unknown said...

That is a big shame I really want some instructions!

Unknown said...

asking for a friend.... would definitely pay some good money for these instructions. What an amazing creation!!

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