Surface bodies have two colors. A front or normal side, and a backside. Solid bodies are colored differently, either by the material or by applying an appearance color.
I can't tell entirely if you you have a mix of solids and surfaces. In the component you have expanded, I can only see surface bodies. You can try to use the stitch command from the modify menu to turn everything into a solid. I can't guarantee the results without seeing the rest of the data in the file. If you want, you can post the file and let us know what you want you final result to be.
Thanks,
Kevin
Kevin Ellingson
Technical Specialist
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