The main goal of this work is to develop a comprehensive methodology for predicting wear in planar mechanical systems with multiple clearance joints and investigating the interaction between the joint clearance, driving condition and wear. In the process, an effective contact surface discretization method together with Lagrangian method are used to establish the dynamic equation of the multibody system. Considering the change of the contact surface, an improved nonlinear contact-force model suitable for the complicated contact conditions is utilized to evaluate the intrajoint forces, and the friction effects between the inter-connecting bodies are discussed using LuGre model. Next, the contact forces developed are integrated into the Archard model to compute the wear depth caused by the relative sliding and the geometry of the bearing is updated. Then, a crank slider mechanism with multiple clearance joints is employed to perform numerical simulations in order to demonstrate the efficiency of the dynamic procedures adopted throughout this work. The correctness of the proposed method is verified by comparing with other literature and simulation results. This study is helpful for predicting joint wear of mechanical systems with clearance and optimize the mechanism’s design.