Last week water found its way into my M5's brake booster.
The M5 forums document that people who have suffered from a similar problem will replace their brake booster to fix it. No mention is made of whether the brake booster is actually salvageable.
Is it possible that the brake booster can be salvaged by simply draining the water out?
What kind of damage could water do to the brake booster internals that would make it unfit for use?