Brake Pedal firm when car is off, when engine is running, goes to floor

[nctexan]

Hey guys thanks for the replies, I've been hammering out alignment and ride height issues, I am going to rebleed either tonight or tomorrow. So by RL, that would imply Rear Left, as in the driver side rear, correct?

 

[DEFIANT 7M]

^:bigthumb:corect, good luck.

 

[Ekmo]

Okay so from what I have learned from reading, your not supposed to bleed your brakes with the car running. The extra pressure from the brake assist will cause any air you have in the system to turn into tiny air bubbles that will stick to your brake lines that you will not be able to get out until the bubbles reform. And from what I remember, when bleeding a vehicle with ABS, you only pump the brake pedal only once. Finally, did you take off one caliper or both? If you did, did you make sure the bleeder valve is at the top?