Proportioning Valve or ABS Module?

At first, my brakes were non-existant. Replaced the brake master cylinder and all was well with the front brakes, but the rear brakes were just dripping brake fluid here or there on both sides. First, does anything with the ABS module/computer thing have to be reset when you replace the master cylinder?

Also, the brake fluid container was dirty but we washed it out with more brake fluid but I'm wondering if some of that junk got into the proportioning valve underneath the master cylinder and has clogged up only my rear lines?

I would like some suggestions or opinions on this if anyone has ran into similar issues.

Thanks!

Must have posted this in the non-tech section.