After I saw pictures of Dennis Bosman's european trucks on the internet (and later at a model show some of his trucks for real), suddenly my old Coke-Truck from my childhood wasn't quite as impressive to me as before. I felt that the whole thing really needed a huge update to be state of the art again.

But after I took some reference pictures of a real Kenworth truck and made some building sketches, I noticed that a simple cosmetic update wasn't sufficient enough, because the scale of my old truck was slightly wrong. The model dimensions didn't match the size of the old 24x43 technic wheels at all.
I would have had to rescale the whole thing, but instead of doing that, I decided to build a truck from scratch (well, a completely new tractor at least). This way I could also keep (as I always intended) the old tractor as a memory of my childhood.

And the bricks of that tractor showed signs of heavy (child-)usage anyway. Due to the new scale, I couldn't utilize parts I used to represent certain things before, e.g. the 24x43 rims for the fuel tanks and the 20x30 rims for the air filters. A solution for new air filters was quickly found, I used the slightly larger model team rims instead.

But for the fuel tanks, I was fiddling around with various parts before I decided to create them using only "standard" bricks.
For the exhaust pipes, a lot of pulley wheels came in very handy.

One goal I wanted to archive was to build openable doors complete with window frames, because I hadn't seen that on any truck model on the net so far. A glove compartment however seemed to be standard equipment.
The rear of the tractor and the trailer both have swing axles.

Additionally, the rear axles of the tractor are suspended by four shock absorbers. The rear axles are connected via differentials and drive the engine under the hood (I know ... should be vice versa).

Below is a WIP picture. I started by building the hood first to see how the whole thing might look using the "new" scale. Later I adjusted the dimensions of the old coke-trailer to fit to the new size of the tractor.

Model dimensions:

Truck:
length: 71cm, width: 20cm, height: 32cm
Trailer:
length: 90cm, width: 20cm, height: 33cm
Truck and trailer:
length: 136cm, width: 20cm, height: 33cm

The first version of this model didn't have an openable hood and a working engine underneath, but later I decided that a perfect model had to had this feature. After I found out which engines go along with the W900L, I paid the Caterpillar homepage a visit to get some reference. Of course I did choose an engine with lots of HP.

It wasn't easy to squeeze the rather long six cylinder engine under the hood. The whole thing - including radiator and fan - is 15 studs long, although the back side of the engine block had to go. Thus the crankshaft ended in the wall separating engine compartment and cabin. But the engine is still driven by the rear axles.

I had to move back the wall to the cabin a bit, because the hood also needed some space to be tiltable. But in the end the six cylinders and the radiator fan were working just fine. To keep the width of the engine as small as possible, I centered the cylinder head so that the whole cylinder block is only 5 instead of 6 studs wide.