What was the reason for replacing the master cylinder? Does the pedal go to the floor? If so here is a guide that will help with that:
In short, there is normally two things that cause this. Either air in the lines or a leak in the system either internally or externally. So if you have bled the system and there is no air then we need to look for leaks. If no external leaks then it would most likely be the master cylinder. Since that has been replaced it is unlikely to be the cause so we need to circle back and make sure there is no air in the system. If you have not put a few bottles of fluid through the system then I suspect there is air in the system.
Also, did you bench bleed the master cylinder? If not there is most likely air trapped in the master cylinder.
Let me know what you find. Thanks
Friday, May 15th, 2020 AT 9:06 AM