Cannot bleed the rear passenger drum brake

Hello,

It sounds like there could be an issue with the brake hose.
Many times, those rubber brake hose collapse on the inside, this creates too much restriction and that reduces brake fluid flow.
It is also possible to have a restriction on anywhere on that line, between the wheel cylinder and the ABS module.

One thing you can try is to remove the brake hose and see if you have better flow from the metal line. If so, then it will tell you the hose is bad.

Please let me know if you have any questions.
Thank you.

https://www.2carpros.com/articles/how-to-bleed-or-flush-a-car-brake-system

So, the issue/restriction could be further up the line.
Do you have any brake related issues before you tried to bleed the system?

So, it sounds like due to the flow issue the brake was not engaging properly.
At this point you will have to trace the brake line and see if you see any type of obvious issues, like outside damage. If there are connections you can remove that connection and check for flow again and work toward the module.
Without figuring out the restriction, you won't be able to bleed the brake properly.

Right, those two out of the master cylinder should go to the ABS module and then four will come out of the module for each wheel. I wonder if something just got out of alignment and creating this issue.

That is good. Glad you got it figured out.