In this article, we show the convergence of a class of numerical schemes for certain maximal monotone evolution systems; a by-product of this resultsis the existence of solutions in cases which had not been previouslytreated. The order of these schemes is 1/2 in general and 1 when the only non Lipschitz continuous term is the subdifferential of the indicatrix of a closed convex set. In the case of Prandtl'srheological model, our estimates in maximum norm do not dependon spatial dimension.