Inertia-free mechanics and the bi-metric procedure

We consider the bi-metric procedure to implement field-theoretical concepts into the mechanical models developped so far in inertia-free gravodynamics. The main result is the fact, that we are able to hide the absolute time underlying the mechanical models for non-gravitational fields by the equivalence principle, but not for the gravitation theory, which reveals the instantaneous gravitational action in one parameter of the post-Newtonian approximation.