Hi everyone,
I've a really anoying brake problem! The brake peddle goes all the way to the floor with engine running. I've bled the system repeatedly and no air or leaks from any of the system!!
when the engine is not running, no brake boost the peddle becomes stiffer and pressure builds turning off brake warning light, but if you leave pressure on brakes it slowly softens and goes to the floor.
I've replaced abs pump brake shoes and pads rear brake lines and changed master cylinder for another used part. !!! Still no joy, still peddle to the floor. Dont understand as I'm not loosing fluid and have no air in system.
do I assume the master cylinder is defective and replace whole uhit or get replacement seal kit.
at my wits end and out of ideas.
Anyone had same problem.

 

Are you sure the m/c you put on there was good? You mentioned it was used.

 

Yes, if the pedal is fading and it's not leaking, the fluid can only be going back into the reservoir.

 

Just going to try and blank the feeds from master cylinder and try brake peddle to see if it still floors, if so I guess it's a new master cylinder.
serves me right for trying used parts !!