Quote:
Originally Posted by benlg81
... the pedel is nice and hard but when you start the car the pedel pressue drops and the pedel goes to the floor
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You expect the pedal to sink a bit when the engine is started as you get a bit of assist (either vacuum assist or hydraulic assist, depending on model).
If the brake pedal is fine when the engine is off, doesn't need pumping to build pressure, doesn't sink slowly to the floor, etc., and only starts misbehaving when the engine has started, then it must be either the master cylinder (seals gone), or the servo assist (Haynes manual should suggest a way of testing).
Are you sure it's completely bled? Did you use a pressure bleeder (or a vacuum bleeder)? If you don't plug the pipe properly when you disconnect something like a rear calliper, you can get air bubbles way inside the pipes. Normal bleeding might not shift the bubble, and the fluid will run clear when it comes out of the bleed nipple. Extended pressure bleeding (could be talking about running a litre of fluid through) should do the trick.
Paul