The automobile horn system is an essential part that produces sound for safety reasons. Production of horn system is classified based on two main processes. One of them is the caulking process which makes body assembly and forms the lower part of the horn system. The control dimension of body assembly is a crucial factor for quality control as the sound of the horn is largely determined by the control dimension. In this paper it has been found that plastic deformation of body and its restoration after caulking process is the main reason for the change in control dimension. Typically, 100 specimens of the body assembly were employed and the results were compared (Restore the Length of the Body) with another data set that had the same body but different parts in the assembly. Monte carlo simulation was used for tolerance analysis of control dimension for the body assembly including the deformation of the body in the caulking process. The simulation was identified as a good model to predict the satisfaction ratio of the control dimension with high accuracy and was observed to be useful in designing parts of the assembly and equipment used in the caulking process.