RE: Bosch cap/possible CH Ignition problem
I would try the liquid electrical tape on it from Harbor Freight. It comes in a 4 ounce bottle with a brush in the cap for areas like yours where dissassembly is not an option to restore the insulation. I've used it on many parts to restore them.
Looks to me, like the mechanical solder joint for the braid shielding is still solid but inspect it closely for cracks or looseness before using the product on it.
John