Due to the classes in object-orientation, which are too detailed and specific, their reusability can be decreased. Components, considered to be more coarse-grained compared to objects, help maintain software complexity effectively and facilitate software reuse. Furthermore, component technology becomes essential by the appearance of the new frameworks, such as MDA, SOA, etc. Consequently, it is necessary to reengineer an existing object-oriented system into a component-based system suitable to those new environments. In this paper, we propose a model-based quantitative reengineering methodology to identify components from object-oriented systems. We expand system model and process, which are defined in our prior work, more formally and precisely. A system model, constructed from object-oriented system, is used to extract and refine components in quantitative ways. We develop a supporting tool and show effectiveness of the methodology through applying it to an existing object-oriented system.