Just in case anyone reading this has the unsettling experience of losing vacuum assist while driving, the brakes will still stop the car. You just have to press the pedal A LOT harder than normal. I experienced this first hand when the vacuum pump on my 240D failed. I got to drive around San Diego for a few days with no power brakes until I scored a used vacuum pump from a junkyard.

For additional fun, I found out after installing the pump, that it interfered with the power steering belt, so I had the other fun experience of getting to drive with power brakes but no power steering until I had the parts and time to repair the original pump. This included driving it from San Diego to Carson City. Actually not bad once rolling, but parking lots were a hundin.

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Whoever said there's nothing more expensive than a cheap Mercedes never had a cheap Jaguar.

83 300D Turbo with manual conversion, early W126 vented front rotors and H4 headlights 401,xxx miles
08 Suzuki GSX-R600 M4 Slip-on 26,xxx miles
88 Jaguar XJS V12 94,xxx miles. Work in progress.
99 Mazda Miata 183,xxx miles.

In my opinion a good driver doesn't really need brakes.