As the title says, I am dealing with soft brakes while the engine is running on my 2000 Toyota 4runner. Prior to this my master cylinder went out. So I have replaced the master cylinder, brake booster, rear wheel cylinders. I have bleed everything properly, I have no air in my lines nor leaks, i do have vacuum on the booster. I have also bleed them several times for countless hours. I also took off the master cylinder and rebleed it thinking there was trapped air, and still nothing. Any ideas out there?