The collective relationships and institutional configurations in a democratic scenario: the Superior Labor Court performance in complying with the collective rights assured by the constitution in the 1990 s, is a study about the institutional configurations in the Collective Labor Relationships sphere. This paper investigates the adopted governmental guidelines that sought to redirect the collective autonomy to make a labor reform feasible. It specifically studies the approach to institutions that determine the legal system of the Collective Industrial Relations of Brazil used by the Superior Labor Court (TST), such as right to strike, collective bargaining, collective dispute, the normative power of the Labor Court, and collective autonomy. The present work deals with the hypothesis that in the 90 s, under the claim of a better collective negotiation, a cracking process in the collective autonomy concept emerged. For that matter, this paper has established a theoretical referential linking together the concepts about trade union freedom and collective autonomy under a normative and institutional prism to provide a more suitable understanding of the relationship between the two normative constitutive instances of the Labor Law - the one that comes from what was covenant collectively, and the other that was legislated - and to establish conceptual bases for the understanding of the collective autonomy (in its triple dimension of self-regulation, self- organization, and self-governing), and its configuration in a legal democratic paradigm. The work show the cracking process in the constitutional concept of the collective autonomy in a background of immoderate increase of the structural instability of power in the 90 s. Such cracking took place not only through the rules, the normative provisions, but also in the interpretation of the constitutive dimensions of the collective autonomy, in which the potentiality of self-organization and self-governing are limited, and the legal effectiveness of self-regulation is overestimated.