GM Brake Master Cylinder With OEM GBM018 18029967 18021273 19209221

The bore diameter of OEM M390259 brake master cylinder is 40mm and 1-1/8″. The fitment is Cadillac 1999-2000, Chevrolet 1994-2000, Dodge 1995-1996, GMC 1994-2000, etc… The size of the two outlet prots is 9/16-18″ & 1/2-20″. The main material is aluminum with the surface to be anodized.