I just went through this on my 1/2 ton. In MA we need to have annual inspections, and they check the parking brake. According to the inspector it needs to hold the truck in gear at 1200-1500 rpms. Not a chance. Even after replacing the brakes, it would barely hold above idle.
I still need to adjust the shoes a little more. I'd actually like to have a functional brake too!
2012 Chevy 2500HD ECSB, 6.0L gas, auto, 4x4, LT
2003 F450, 7.3L PSD, 6 spd stick, 2wd, dump truck
1983 GMC K2500 pickup - working on a Cummins 5.9L swap
1987 GMC K3500 Dump, 6.2L diesel, TH400 auto - project plow truck