67-68 Chevelle & El Camino w/ factory disc brakes
This is the golf ball size valve that hangs off the driver side stud of the master cylinder. This hold off valve came on all factory disc brake cars. It is part one of the two or three part valve system. All the cars, whether disc or drum, had the same valve on the frame (see part #DM93020). The disc cars had this hold off valve in addition to the frame valve. They must be used together.