need help with brake booster!!! 67 c10

[xguzman13x]

i need help. i got a 67 c10 that had all drum brakes and no booster. my uncle had a donor truck, 73 c10 with front disc and rear drum, so i took his front spindles and rear brakes and booster. i installed the used booster onto my 67 c10 with new master cyl, new calipers and pads, new wheel cylinders, new shoes, new rear drums and all new brake lines. so the only used parts were the brake booster and pro. vavle from the 73 c10. now the problem is that when i turn on my motor and apply the brakes, my pedal goes all the way down and doesnt come back up. and all brakes are locked up. i cant even pull it back with my hands. then i turn of the motor and the pedal comes back up. is this a problem of a bad booster? bad pro. vavle? idk but i cant seem to find the problem.

[Scottshotrods]

I would change out the brake booster on your truck

Justin