Rear Drum Brake Backing Plate to Axle Gaskets, 2pc Applications 1964-72 A-body, , , , 1967-69 F-body, , 1968-74 X-body, , , , 1970-81 F-body, , 1973-77 A-body, , , , 1964-72 Elcamino, 73-77 Elcamino 1970-72 , 69-72 All other GM Cars with 9 1/2 rear drum brakes. These are used between the axle flange and the drum backing plate. If these are not in place the axle lube slowley works to the end of the axles out the ends and coats the brake backing plates and inner drum wetting the shoes causing them not to work. The original cars had a thin metal gasket that once removed can seldom be reused.