Cleaning inside the A/C system ('87 300E)?
While replacing the compressor, drier & expansion valve, I have run into troubling reports (from a local mercedes parts & repair poviser) regarding failure rates on A/C repairs. He reports that over the last twenty years he has tried most "reputable" brands of rebuilt compressors, including rebuilds supplied by mercedes, and has never found what he feels is a consistent supply of rebuilt compressors.
More troubling, he reports that it is almost impossible to adequately clean the manifold hoses assembly that attaches to the rear of my compressor.
Tonight, after removing the manifold from the old compressor and cleaning it with brake cleaner, I noticed that one side of the ports was still covered with a dark gray film. A shop rag produced black residue after minor rubbing inside the ports. No amount of brake cleaner will touch the film. This film also exists in the manifold hose assembly (at least at the metal portion that bolts to the A/C compressor manifold).
If this type of film is spread throughout the system, prehaps this is the casue of post-rebuild failures.
Does anyone have expertise that can help me get my system adequately clean inside?
Also, what is the track record regarding the life of the stock condensors.