PurposeThis study aims to improve the reception and positioning of materials in the warehouse, as well as the internal logistics of a bus manufacturing company by acting upon the processes of supply line management.Design/methodology/approachThis study is based on the action research methodology which, through a practical approach, intends to generate transferrable knowledge to other organizations whose situations are similar to that of this study. The practical actions and the knowledge acquired co-create the changes needed for the improvement processes.FindingsThrough these improvements, it is possible to standardize supply and eliminate the retention of picking carts on the line, simplify the management of materials provided in supermarket boxes, improve the control of materials and facilitate the process of picking and materials storage. A kanban card-based supply system was also expanded to the bus assembly line, allowing more control over valuable materials.Originality/valueThis study has demonstrated how the implementation of lean techniques on a bus assembly line can lead to increased consistency of supply to the line and improved working conditions, both in the production and warehouse areas. Furthermore, it has set a new standard of the internal logistics processes and the inclusion of process recording in the working instructions.