Gary Olby

Having difficulty finding a wheel cylinder for a 1979 Buick Regal Ltd. 4.9 engine. This car has 9.5 inch drums. Trying to bleed brakes and bleeder broke off from being rusted in place. I have ordered 4 different wheel cylinders which are stated to fit this car but do not. Any assistance on part numbers will be appreciated. This wheel cylinder has a snap ring type fastener and no extra c type collar on the cylinder. Gary