My Brake fluid was Black I tried to purge my system using the Harbor Freight, Pittsburg Pneumatic Brake bleeder and I could not even get fluid to flow to my rear breaks. too a closer look at rear breaks and I could not even get them apart. the Break shoes had worn a groove into the drum making a lip on the edge that I could not get the passed the brake shoes. I ended up taking apart everything and after a whole day long ordeal of drilling and prying I got them removed and replaced with all new parts. Still no flow using break bleeder. has anyone used this type of a brake bleeder before is there something different about the Chevy brakes that is wont work with?