The old Lego Technic Bulldozer was published in 1993 under the set number 856. It has a total of 172 pieces of Lego, 46 individual Lego parts+2 rubber bands. The rig sould be identical to the original model. I made two easy sliders for the main arms, and a simple object to move the whole Bulldozer.
Note: It's possible to tweak the slider who controls the shovel too much, thats because it's rotating limit changes as the main arm gets lifted/lowered(so keep that in mind when you move the main arm up and down).
I must say that I enjoyed every little part of this project, and I hope you will enjoy it as much as I did^^
Link to HD wallpaper:
Here is the original Lego instruction for the Bulldozer: