750li brake issue

2006 bmw 750li.

The brakes feel as if they have no assist. The pedal doesnt go to the floor, but requires the force of a gorilla to stop the car. The faster im going, the easier it stops, yet as i approach around 30 to 25 mph it becomes extremly difficult to stop.

I have;

  1. changed front and rear pads and roators (seems slightly worse since. Roators were pretty worn, pads were so-so, not that bad)
  2. Checked the break booster via the car on/off pedal movement methods, and everything is normal.
  3. pulled the vacuum line, and without a gauge, the vacuum seems to be plenty. Check vavle seems also ok
  4. Aware of the recall, car was taken in 2013 for it, but no issues were found then, and i found none now. There is no presence of oil around the vavle or anywhere in that area.
  5. checked everything for leaks, none present, and brake fluid is exactly on the max line in the res.
  6. have not bleed the brakes. My wife is scared of bmw’s and i dont have many friends to help. But as to that, there should be no air in there in the first place.

Any ideas would be awesome

Sounds to me like the booster has failed internally.


You may be correct. Now i can hear a slight hiss when i press the brake. There is no hint of stalling though, and if i pump the brake when off, and turn the car on the pedal does drop a couple of inches. I suppose it still is the booster.