brake problem, broken pushrod or booster, now what?

[sactoC10]

For three weeks I've been trying to fix my "sticking brakes" problem. Fluid, hoses, bleeding, not even a new master cylinder resolved it. So finally last night after repeated attempts at bench bleeding and wheel bleeding unsuccessfully I thought it through further.

Since the master cyclinder is new and working correctly, what could possibly be causing such ANXIETY, STRESS and FRUSTRATION? I think I found out, but I need confirmation.

I have power brakes and thus a booster. The long pushrod that goes through the booster, yup..think mine is broken and getting stuck INSIDE the master cylinder, not allowing my brakes pads and shoes to"back off" and cool off. But when the truck sits overnight, everything slowly migrates back into place, causing all sorts of confusion.

So what is my fix? Pushrod alone? Or whole new booster? If I need an entire new booster, what other chevy makes and years might this one be interchangeable with? I have a 71 350.

Thanks again.