Delco-Moraine Single Diaphragm

A combined vacuum-hydraulic unit which uses a combination of intake manifold vacuum and atmospheric pressure to provide power assist. Reserve vacuum supply and vacuum check valve allow several brake applications, with vacuum assist, after engine has stopped.

Unit is composed of 2 main sections, a vacuum power cylinder and a dual master cylinder. Vacuum power cylinder contains the power piston assembly, which houses the control valve, reaction mechanism, and power piston return spring.