We study the role of endogenous formation of institutions in overcoming coordination failures in weakest-link games in fixed neighborhoods, aiming at higher public good provision levels. The weakest-link game characterizes environmental problems where the action of the lowest effort defines outcomes for a group (e.g. dike protection or fighting wildfires). The institutions that we consider are weak, in that they only form and take decisions by unanimity and have no enforcement power. Our experimental results show that such institutions are formed and that they facilitate overcoming the coordination problem, raising equilibrium provision levels. However, institutions do not trivially solve the coordination problem. As the data shows, also institutions fall short of providing Pareto-optimal contributions. Given the multiplicity of Nash equilibria in weakest-link games, we provide a Quantal Response Equilibrium (QRE) and an Agent QRE analysis to rationalize our experimental results. We demonstrate that institutions would solve the coordination problem with (almost) perfectly rational agents, and that our experimental results are consistent with (A)QRE models with bounded rationality.