shoeless,
If your parking brake pull rod assembly looks like the assembly in the diagram below, from the 47.5-54.5 Factory Assembly manual, spring 369935 and rod 3687278 (on 1/2 ton) should provide enough return "tension" to almost slam the parking brake pedal back into the released position.
Do you know if all privot points from the pedal to the rear cross shaft and the brake cables themselves were moving freely? In particular, the cables often get rusty and bind inside their housings.
Tim
http://home.nycap.rr.com/lederman/images/pkgbrkspring.jpg
