Abstract Generally, multi-body mechanical systemsin which the impact phenomena occur exhibit chaoticand quasi-periodic behavior. Mechanisms with clearance joint are categorized in such systems due to contact between the connecting bodies. In this paper, wewould investigate the nonlinear dynamic behavior of afour-bar mechanism with joint and clearance at the connection between the coupler and rocker. Motion equations are derived based on the Lagrangian approach.The nonlinear continuous contact force model proposed by Lankarani and Nikravesh is utilized to evaluate the normal contact force developed in the journal–bearing system. Furthermore, the friction effect on theclearance joint is considered using a modified Coulombfriction law. The dynamical behaviors are numericallyidentified in discrete state space, based on the Poincaréportraits. Numerical simulations display both periodicand chaotic motions in the system behavior. Therefore,bifurcation analysis has been performed with a changein the size of clearance corresponding to the variousvalues of crank rotational velocities. Then, we comparesome clearance ranges, in which the system response becomes stable for these cases. Fast Fourier transformation is also applied to analyze the frequency spectrum of the system response