Hey guys I'm new on here figured I'd make a post. I have a 53 Chevy 1.5 ton flatbed I've been working on. Original drivetrain with some minor upgrades....working on my brakes now mounting an under the floor vaccum booster and dual master cylinder. Hoping to find some answers on what could be wrong or what I should do differently. I'll post pictures but what I did was make a new bracket and rod and mounted a vaccum booster for a 75 c30 Chevy mounted to a late 70s p30 master with 1.25 bore for power drum brakes. I then added residual valves in line and used the original vaccum line that ran to the old hydrovac system to the new vaccum booster. But only problem is that I cant seem to get brakes!!! Its like no pedal and i really dont understand what could be the trouble. I've seen many other have had success but mine has the two wheel cylinders in the rear drums does that make a difference?? Any advice would help!!