Technical Galaxie brakes..dual master problem

My Galaxie has drum brakes all around. I did convert to, i believe a mid sixties style dual reservoir ( the one that has the center bolt for the lid). After my brkes were ok/good but when i got on them hard my left front would lock up. I have since replaced everything up front(cylinders,shoes, rubber lines, drums) and now they seem very mushy. Moving it around a parking lot the seem fine, trying to stop at a 45 roll i really have to get on them,but still not a hard petal. So i believe i probably need one of the residual pressure valves, my lines are connected directly to the master(front to master rear, rear to master front). Does this seem like a plausible ***umption. And why were the brakes fine before, Ive never herd of wheel cylinders having residual valves.
Thanks,
Jim

 

If your new master is a drum / drum unit it should have check valves built into it.

They sit behind the br*** ferules in the master cylinder.

 

What year Galaxie? The master you describe seems to be for a Mopar since it had the center cover bolt. If the drum brakes are ***embled correctly, adjust them up (evenly as possibly up front) and bleed it again. Is the master old or new? For the locking up, check the shoes for contamination, brake fluid or grease can do it.

 

What method are you using to bleed the brakes? That can be your problem. You never want to “ build a pedal” and then open a bleeder. If there is any air in the system, when you build a pedal, it can shoot air all through the system, therefore making bleeding impossible.
With two guys, have one open the bleeder as the other slowly pushes the brake pedal down. When the fluid stops flowing, close the bleeder before the pedal is released. Repeat on all wheels, till solid fluid comes out. Note, check your master cylinder reservoir often, don’t let it go dry, during the bleeding process.

Bones