Part Type: Brake Master Cylinder Reservoir Cap Gasket. 1974 Ford Mustang II. 1975 Ford Mustang II. 1976 Ford Mustang II. 1977 Ford Mustang II. 1978 Ford Mustang II. Manufacturer: Dorman. To confirm that this part fits your vehicle, enter your vehicle's Year, Make, Model, Trim and Engine in theCompatibility Table.