Abstract: A master cylinder has a sheet metal reservoir divided into reservoir chamber sections by a molded nylon baffle inserted in the reservoir and held in place due to an interference fit across the width of the reservoir. The baffle has a portion providing a spring-like action which maintains a continuous force tending to hold the baffle in place. The baffle is constructed as a plate with pad sections engaging the reservoir side walls, the plate being separated into sections by a generally cylindrical compression ring which provides the desired resiliency. The edge of the baffle engaging the reservoir bottom is shaped to fit the contour of the bottom. At least a part of this edge is feathered or tapered to allow it to more readily conform to the bottom.