The mounting plate system is for use with a prosthetic socket, the socket having at least one aperture in a distal end thereof and in fluid communication with an interior portion of the socket which receives a residual limb. The mounting plate system includes a mounting plate having a top face to interface with the socket, and a bottom face for attachment to lower portions of a prosthetic limb. An opening in the mounting plate extends from the top face to the bottom face thereof, and a valve housing is positioned in the opening and has a channel therein for fluid communication with the interior portion of the socket via the at least one aperture. A one-way expulsion valve is secured between the valve housing and the socket adjacent the aperture and for regulating fluid communication between the interior portion of the socket and the channel in the valve housing. A vacuum reservoir seal plate is also provided.
