This paper focuses on maintenance optimization strategies in complex manufacturing systems under uncertainty of available resources and tasks duration constraints. We propose a deterministic formulation of the maintenance optimization problem and provide a chance constraints modeling to formulate uncertainty constraints. Our stochastic mathematical model is reformulated using approximations providing deterministic equivalent formulations that we solve in negligible times to reach near global solutions. Simulation results are provided to illustrate the efficiency of our mathematical models when highlighting the convergence of the chance constraints formulation to the deterministic form for given confidence levels.