Philippe,
Getting the factory part numbers is crucial in sourcing parts for vehicles so old, it is especially so with larger trucks as there is little aftermarket support. Securing a parts manual should be high on your wish list. I hope you have found a brake spring pliers as those springs are quite difficult to install without one...unless you have Popeye like forearms. The wheel cylinders look to be relatively new as the first time I noticed Argentinean brake parts to come on the market was only about 5-6 years ago. Hopefully chemists in Argentina are better at reproducing rubber components than those in China. The axle to hub terne plate seal on your truck may be the same as used on military trucks of similar age. Give me some dimensions and I can compare. If so, I have very reasonably priced sources.
Paul
