2012 Tundra, 4.6L, 86,000 miles 2WD, 3/4 door in the rear. So the pedal goes to the floor when engine is running and making a stop. With engine off pedal hard when starting pedal goes to the floor. Vaccuum pump also used to bleed the brakes. Master cylinder replace twice, second cylinder from the dealer. When driving pedal feels like it will work then goes to the floor. Lines bled several times, no air in the system. No codes or light to indicate bad ABS module. Hard pedal with engine off to indicate brake booster is working. No leaks at the calipers or in the lines that could be seen, no brake fluid lost in the master cylinder, still at full level. So what can it be, any help would be greatly appreciated, as I am out of ideas. Thanks
check for leaks in the booster
@imperator : Hi, thanks for the reply. How do I check for leaks, I don't hear any air escaping, is there a certain way to check for leaks on the booster.
it's useful to have a service manual if you plan to be doing your own brake work