Abstract: A prosthetic limb socket assembly includes a bleeder valve configured to automatically adjust vacuum pressure within the prosthetic limb socket based upon a difference in ambient air pressure and vacuum pressure within the prosthetic limb socket. The bleeder valve includes: a housing having a first end, a second end, and channel extending therethrough providing fluid communication between the ambient and the interior of the prosthetic limb socket; and a valve disc disposed within the channel and biased into a substantially sealed engagement with a valve seat, wherein a certain pressure difference between the ambient and the interior of the prosthetic limb socket is operative to overcome the bias and unseat the valve disc from the valve seat.