Remember the high pressure fuel pump mess from the BMW E90 335 a few years ago? Well according to this post on Reddit, the BMW F30 328i camshaft might not be drilled properly to provide oil to the vacuum pump resulting in failure of the power brakes. It looks like the vacuum pump/ power assisted brakes problem has been going on for months based on the comments from F30 owners on F30post.com

A faulty fuel pump simply leaves you stranded. This problem leaves you without brakes. Sure they work if you have strong legs, but what if you let your mom take one to the store? Is she strong enough to stop a modern BMW without power assisted brakes?