The primary goal of the project is to design a hydraulic disk brake system for mountain bikes made from reinforced plastics. Hydraulic brakes offer significantly better performance for a mountain bike over traditional cable rim break or cable disk break. Nevertheless, people are unable to appreciate advantage because of the price. The traditional hydraulic disk brake systems are made of aluminum alloy. With a proper design, it may be possible to create a lever assembly and a caliper that would be competitive on price and weight. Often bike parts are judged by how much they weight, the less they weight, the more they are desirable. This is only true to a certain extent because lighter parts come with a premium price tag. The current project proposed that the injection molded brakes would be lighter because of the material being used and cost-effective because the manufacturing process can be utilized. Commercial reinforced plastic composites have been identified as lighter materials compared to aluminum alloy. Through an iterative design process, the final designs of lever assembly and caliper have been achieved. The stopping force has been determined considering the abrupt stoppage with a standard weight person riding the bike. Based on the stopping force the stress analyses were obtained using FEA simulation for master cylinder, slave cylinder, and lever. At the end, the final designs were chosen based on the stress analyses and manufacturability.