'73 Swinger brake drag

Brettbot said
View attachment 1715993671
I believe this is the proportioning valve, right?

I appreciate the reply! I'll take a look into the residual valve when I get the chance.

Yep! That’s the prop valve and it looks like the right one for a disk/drum car.

That front brake line coming off the top right looks pretty beat up, that could be an issue as well.

The residual valve shouldn’t be there on a disk/drum master cylinder, but stranger things have happened when stuff gets swapped, replaced or rebuilt.