The brake pedal in my car goes all the way to the floor and the two "professional" mechanics I've taken the car to have replaced the master cylinder and bled the brakes and still don't know what the problem is...they said it could be the brake booster but it would cost $800 to fix! Could it be the brake booster? There has been major leaking over time from under my car onto the street I park on that has stained the road. If it is the brake booster could I just replace it myself or would it be too difficult for someone other than a professional? Thank you very much for your time!