The automotive sector is facing the challenge to become more resource-efficient in the manufacture of cars and their components. One approach is to increase the share of recycled materials. This paper presents the results of a case study for the automotive sector of the EU-funded Zerowin project. A safety-relevant component of the braking system was selected for manufacture using a mechanically recycled composite plastic material (polyethylene terephthalate reinforced with short glass fibres). The case study demonstrated the interdependencies between material and component specification, component design, material properties and the production process: using recycled glass-fibre-reinforced plastics for a safety-relevant component is not just an issue of input substitution, it is an interplay of technological (product development, production process modification, recycling process), organisational (security of supply, network infrastructure) and economic (material cost savings versus adjustment costs, planning horizons) factors resulting from the input substitution of primary material and changes of material properties. An industrial network was established and the case study's findings were transferred to serial mass production. Industrial networks are seen as an appropriate tool for securing the supply and quality of recyclates from traceable sources.