I did it but i losed all my owb guns and hh guns but kept dead money thank god i saved before i did clear cache then deleted the update anyone no why it did this hellppp

. . . what?

Because you need the patches for the DLC's to work; without them, it won't be able to register the DLC (at least that's how I think of it) until the patch is reinstalled. As for keeping Dead Money, I have no idea why that happened.