Not getting brakes fluid to the back brakes

Good morning.

Check the rear brake hoses to be sure they ar not collapsed from the hose restricting the flow of fluid.
Also, it could be the ABS unit not passing fluid to the rear wheels.

Roy

Did you just replace a brake line or something and trying to use a vacuum bleeder?Because from my experience it is very difficult to use a vacuum bleeder after replacing an entire brake line. I found out I at least had to use the old foot bleeding method first before most of the air is out of that line.