Brakes failed, car rolled back dangerously

[13brian]

Glad to hear that you found it. You're back up and running. More glad it was not catastrophic failure causing more damage.

[byaru1]

Originally Posted by 13brian

Glad to hear that you found it. You're back up and running. More glad it was not catastrophic failure causing more damage.

Ohh yessss.. I'm thankful it did not occur on a highway or some place where the situation would have been more catastrophic.

Sent from my SM-G990U1 using Tapatalk

[byaru1]

Originally Posted by byaru1

Ohh yessss.. I'm thankful it did not occur on a highway or some place where the situation would have been more catastrophic.

Sent from my SM-G990U1 using Tapatalk

So after the M/C was replaced, the x5 brakes well, but it looks like after the engine has heated up, like driving 20 minutes, the brake pedal softens again, much as the car still stops.

Could this be bad brake fluid or air in the system, or both?

Sent from my SM-G990U1 using Tapatalk

[wfwright2]

Could be air or moisture in the system, could also be a vacuum issue somewhere between vacuum pump and brake booster.
Tech did a system bleed as well as a M/C bleed when replacing the M/C hopefully so there should only be fresh, air free fluid in the braking system.
It is somewhat normal for the brakes to feel a little "soft" with the engine running as compared to a shut down system that the vacuum assist is not available. But pedal should not move to the floor.

Sent from my SM-T377V using Tapatalk

[ard]

Did the tech have the BMW computer (or fox well tool or whatever) that allows a complete and proper bleeding of the fluid to make sure the ABS pump and valve have been flushed and no air remain??