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Hmmm. I seem to have avoided that kind of problem so far...in 12 yaers anyway. But I do run cleaner through it every month.
There was one part on ours where it seemed impossible to get the part off without breaking it - there was a retaining tab that couldn't be reached. I fixed it back on with a strategically drilled hole and a nylon nut and bolt. I now have the spare part for next time (it was the hose retainer). If a new part comes with it, it may well need to be broken.
Have you looked on the Bosch site? They have exploded diagrams - I always get Bosch spare from there (but other spares from espares).
Without knowing the exact model number I can't look on the Bosch site - you need the 'E-Nr' which is usually engraved on the top edge of the door.