Front drum brakes not working

[chadcampbell00]

I have a 1970 Jimmy with front drum brakes. Everything in the braking system is new (booster, master cylinder, lines, drums, shoes). My problem is that only my rear brakes work. When I bleed the front they seem to have pressure. I tried putting a proportioning valve in to cut back the pressure to my rear but that caused me to not have hardly any brakes at all. I can adjust the front to seem to work on a jack stand but as soon as I drive off nothing. Does anyone have any advise that may help